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new to Virtual Tape Library - what are the benefits?

Posted by Anonymous 
new to Virtual Tape Library - what are the benefits?
August 14, 2007 03:02AM
Hi, I am new to the use of VTL (clariion disk) and I would like to know what the benefits of using the VTL are over using Advanced Disk Device.
Also, is there such thing as staging on a VTL? If not then what is the best way to free up disk space when it is full - is it cloning to tape and then re-labeling the virtual media.

Any examples of how you are using VTL and managing the media would be appreciated.

Regards, Mark

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new to Virtual Tape Library - what are the benefits?
August 14, 2007 08:20AM
First thing you need to wrap your arms around is that to Networker, a
VTL is just another jukebox. Therefore, whatever you can do to a
physical library (staging, cloning, etc), you can do to a VTL. Took me
about 5 months to get that figured out.

We currently are using an EMC CDL 710 for our VTL and I have 1 ADIC
I2000 created on it. We also have an ADIC I500 in house for our
physical tape library needs. The I2000 runs 32 LTO3 drives and the I500
has 4 LTO3 drives. The intent of the I500 is to have that be at our DR
site (in construction/planning stages), but for now, it sits in the
datacenter.

All of our backups go to the CDL first and then will be staged to the
I500 (still completing this process). I was doing automatic cloning of
the backups from CDL to Physical, but that was basically duplicating
savesets and staging will delete the savesets once they are moved over
to the physical storage, then the physical tapes move to our offsite
vaults.

That's a 1000 foot view of our environment today. If you need/want
more, just ask.

Goodluck!

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of mark wragge
Sent: Tuesday, August 14, 2007 6:03 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: [Networker] new to Virtual Tape Library - what are the
benefits?

Hi, I am new to the use of VTL (clariion disk) and I would like to know
what the benefits of using the VTL are over using Advanced Disk Device.
Also, is there such thing as staging on a VTL? If not then what is the
best way to free up disk space when it is full - is it cloning to tape
and then re-labeling the virtual media.

Any examples of how you are using VTL and managing the media would be
appreciated.

Regards, Mark

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new to Virtual Tape Library - what are the benefits?
August 14, 2007 03:57PM
Essentially you can get disk to disk backup speeds, and can do dynamic drive
sharing. Of course, you do loose the ability to read and write at the same
time, that you get from an advanced file type device.

With the latest versions of NW you can use the processors inside the EDL
(new name for the CDL) as a storage node to do the cloning/migration to tape
for you.

7.4 has new licensing for VTL's - watch out for that.

Siobhan

On 14/8/07 8:02 PM, "mark wragge" <mark_t_wragge < at > YAHOO.IE> wrote:

[quote]Hi, I am new to the use of VTL (clariion disk) and I would like to know what
the benefits of using the VTL are over using Advanced Disk Device.
Also, is there such thing as staging on a VTL? If not then what is the best
way to free up disk space when it is full - is it cloning to tape and then
re-labeling the virtual media.

Any examples of how you are using VTL and managing the media would be
appreciated.

Regards, Mark

Send instant messages to your online friends http://uk.messenger.yahoo.com

"signoff networker" in the body of the email. Please write to
networker-request < at > listserv.temple.edu if you have any problems with this list.
You can access the archives at
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

[/quote]

Siobhán

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new to Virtual Tape Library - what are the benefits?
August 14, 2007 04:15PM
[quote]Essentially you can get disk to disk backup speeds, and can do dynamic drive
sharing. Of course, you do loose the ability to read and write at the same
time, that you get from an advanced file type device.
[/quote]
If you are into staging savesets around, you will also not free up space
until all the savesets on the tape have been staged...

I personally think that it is better to invest in more space for your
ATFD

Best
Dag

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new to Virtual Tape Library - what are the benefits?
August 15, 2007 06:32AM
Can you give some details about how licensing changes for VTLs in 7.4?

Thanks.
Teresa

-----Original Message-----
From: EMC NetWorker discussion [mailto] On Behalf Of Siobhán Ellis
Sent: Tuesday, August 14, 2007 6:57 PM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the benefits?

Essentially you can get disk to disk backup speeds, and can do dynamic drive
sharing. Of course, you do loose the ability to read and write at the same
time, that you get from an advanced file type device.

With the latest versions of NW you can use the processors inside the EDL
(new name for the CDL) as a storage node to do the cloning/migration to tape
for you.

7.4 has new licensing for VTL's - watch out for that.

Siobhan

On 14/8/07 8:02 PM, "mark wragge" <mark_t_wragge < at > YAHOO.IE> wrote:

[quote]Hi, I am new to the use of VTL (clariion disk) and I would like to know what
the benefits of using the VTL are over using Advanced Disk Device.
Also, is there such thing as staging on a VTL? If not then what is the best
way to free up disk space when it is full - is it cloning to tape and then
re-labeling the virtual media.

Any examples of how you are using VTL and managing the media would be
appreciated.

Regards, Mark

Send instant messages to your online friends http://uk.messenger.yahoo.com

"signoff networker" in the body of the email. Please write to
networker-request < at > listserv.temple.edu if you have any problems with this list.
You can access the archives at
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

[/quote]

Siobhán

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new to Virtual Tape Library - what are the benefits?
August 15, 2007 07:01AM
So, how does de-duplification fit into this? Is the capacity based on how much is backed up (when calculated at the client)? Or is it by how much space it takes up? Actually, I'm wondering that same thing for AFTDs.

Thanks.

Teresa

________________________________

From: Attila.Mester < at > Sun.COM [mailto]
Sent: Wednesday, August 15, 2007 9:49 AM
To: EMC NetWorker discussion; Teresa Biehler
Subject: Re: [Networker] new to Virtual Tape Library - what are the benefits?

The 7.4 release has a real VTL license, based on capacity, 10TB base, 10TB and 25TB additions. There is also a special storagenode license available for Clariion Disk Library. Prior to 7.4, customers got 3 x Unlimited Autochanger Licenses when licensing VTLs, even after introduction of the mentioned capacity based model.
regards -attila

Teresa Biehler schrieb:

Can you give some details about how licensing changes for VTLs in 7.4?

Thanks.
Teresa

-----Original Message-----
From: EMC NetWorker discussion [mailto] On Behalf Of Siobhán Ellis
Sent: Tuesday, August 14, 2007 6:57 PM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the benefits?

Essentially you can get disk to disk backup speeds, and can do dynamic drive
sharing. Of course, you do loose the ability to read and write at the same
time, that you get from an advanced file type device.

With the latest versions of NW you can use the processors inside the EDL
(new name for the CDL) as a storage node to do the cloning/migration to tape
for you.

7.4 has new licensing for VTL's - watch out for that.

Siobhan

On 14/8/07 8:02 PM, "mark wragge" <mark_t_wragge < at > YAHOO.IE> <mailto:mark_t_wragge < at > YAHOO.IE> wrote:

Hi, I am new to the use of VTL (clariion disk) and I would like to know what
the benefits of using the VTL are over using Advanced Disk Device.
Also, is there such thing as staging on a VTL? If not then what is the best
way to free up disk space when it is full - is it cloning to tape and then
re-labeling the virtual media.

Any examples of how you are using VTL and managing the media would be
appreciated.

Regards, Mark

Send instant messages to your online friends http://uk.messenger.yahoo.com

"signoff networker" in the body of the email. Please write to
networker-request < at > listserv.temple.edu if you have any problems with this list.
You can access the archives at
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

Siobhán

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--
********************************************************************
Attila Mester 5 Digit Sun internal: x62534
Data Protection Architect Tel: (+49 89) 46 008 2534
Sun Microsystems GmbH Fax: (+49 89) 46 008 2583
Sonnenallee 1 Mobil: +49 172 812 5947
85551 Heimstetten / Germany mail: attila.mester < at > sun.com
********************************************************************

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new to Virtual Tape Library - what are the benefits?
August 15, 2007 07:09AM
What counts is only the usable disk space (usable, not the raw disk
capacity) in the VTL disk cache. Lucky you, if you can fill this
efficiently with de-duplication. The same thing applies to FTD or AFTD.
BTW, one of the other benefits of using VTL from the licensing point of
view is, you can define a large number of devices which you dedicate to
the storagenodes, so eliminating the need of using expensive DDS (drive
sharing) license options.

regards -attila

Teresa Biehler schrieb:
[quote]
So, how does de-duplification fit into this? Is the capacity based on
how much is backed up (when calculated at the client)? Or is it by how
much space it takes up? Actually, I’m wondering that same thing for AFTDs.

Thanks.

Teresa

------------------------------------------------------------------------

*From:* Attila.Mester < at > Sun.COM [mailto]
*Sent:* Wednesday, August 15, 2007 9:49 AM
*To:* EMC NetWorker discussion; Teresa Biehler
*Subject:* Re: [Networker] new to Virtual Tape Library - what are the
benefits?

The 7.4 release has a real VTL license, based on capacity, 10TB base,
10TB and 25TB additions. There is also a special storagenode license
available for Clariion Disk Library. Prior to 7.4, customers got 3 x
Unlimited Autochanger Licenses when licensing VTLs, even after
introduction of the mentioned capacity based model.
regards -attila

Teresa Biehler schrieb:

Can you give some details about how licensing changes for VTLs in 7.4?

Thanks.
Teresa

-----Original Message-----
From: EMC NetWorker discussion [mailto] On Behalf Of Siobhán Ellis
Sent: Tuesday, August 14, 2007 6:57 PM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU <mailto:NETWORKER < at > LISTSERV.TEMPLE.EDU>
Subject: Re: [Networker] new to Virtual Tape Library - what are the benefits?

Essentially you can get disk to disk backup speeds, and can do dynamic drive
sharing. Of course, you do loose the ability to read and write at the same
time, that you get from an advanced file type device.

With the latest versions of NW you can use the processors inside the EDL
(new name for the CDL) as a storage node to do the cloning/migration to tape
for you.

7.4 has new licensing for VTL's - watch out for that.

Siobhan

On 14/8/07 8:02 PM, "mark wragge" <mark_t_wragge < at > YAHOO.IE> <mailto:mark_t_wragge < at > YAHOO.IE> wrote:

[quote]Hi, I am new to the use of VTL (clariion disk) and I would like to know what
the benefits of using the VTL are over using Advanced Disk Device.
Also, is there such thing as staging on a VTL? If not then what is the best
way to free up disk space when it is full - is it cloning to tape and then
re-labeling the virtual media.

Any examples of how you are using VTL and managing the media would be
appreciated.

Regards, Mark

Send instant messages to your online friends http://uk.messenger.yahoo.com

"signoff networker" in the body of the email. Please write to
networker-request < at > listserv.temple.edu <mailto:networker-request < at > listserv.temple.edu> if you have any problems with this list.
You can access the archives at
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

[/quote]

Siobhán

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

--
********************************************************************
Attila Mester 5 Digit Sun internal: x62534
Data Protection Architect Tel: (+49 89) 46 008 2534
Sun Microsystems GmbH Fax: (+49 89) 46 008 2583
Sonnenallee 1 Mobil: +49 172 812 5947
85551 Heimstetten / Germany mail: attila.mester < at > sun.com <mailto:attila.mester < at > sun.com>
********************************************************************

[/quote]

--
********************************************************************
Attila Mester 5 Digit Sun internal: x62534
Data Protection Architect Tel: (+49 89) 46 008 2534
Sun Microsystems GmbH Fax: (+49 89) 46 008 2583
Sonnenallee 1 Mobil: +49 172 812 5947
85551 Heimstetten / Germany mail: attila.mester < at > sun.com
********************************************************************

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 16, 2007 03:39AM
Does this mean that there is a way to stage data from a VTL to physical tape? Is this controlled from networker administrator staging OR from the VTL administration software?

At the moment we are cloning from VTL to physical and then re-labeling the VTL tape to free up space. is there a better way requiring less manul intervention to free up disk space (assuming that retention periods cannot be changed).

Thanks again for all these tips.

Dag Nygren <dag < at > NEWTECH.FI> wrote:
[quote]Essentially you can get disk to disk backup speeds, and can do dynamic drive
sharing. Of course, you do loose the ability to read and write at the same
time, that you get from an advanced file type device.
[/quote]
If you are into staging savesets around, you will also not free up space
until all the savesets on the tape have been staged...

I personally think that it is better to invest in more space for your
ATFD

Best
Dag

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

Send instant messages to your online friends http://uk.messenger.yahoo.com

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 16, 2007 07:01AM
Depending on the VTL involved, it will manage the cloning of data to physical tape. If this is license-free, then it may be better to do this than to involve NetWorker, which will require a further jukebox license to cover this. The way it works on a CDL is that the CDL controls the physical library, and will load tapes and route the data to NetWorker that way. Or so I believe - didn't have physical libraries on my last job :)

Cheers,

Stuart.

________________________________

From: EMC NetWorker discussion on behalf of mark wragge
Sent: Thu 16/08/2007 11:39
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the benefits?

Does this mean that there is a way to stage data from a VTL to physical tape? Is this controlled from networker administrator staging OR from the VTL administration software?

At the moment we are cloning from VTL to physical and then re-labeling the VTL tape to free up space. is there a better way requiring less manul intervention to free up disk space (assuming that retention periods cannot be changed).

Thanks again for all these tips.

Dag Nygren <dag < at > NEWTECH.FI> wrote:
[quote]Essentially you can get disk to disk backup speeds, and can do dynamic drive
sharing. Of course, you do loose the ability to read and write at the same
time, that you get from an advanced file type device.
[/quote]
If you are into staging savesets around, you will also not free up space
until all the savesets on the tape have been staged...

I personally think that it is better to invest in more space for your
ATFD

Best
Dag

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Send instant messages to your online friends http://uk.messenger.yahoo.com http://uk.messenger.yahoo.com/

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 16, 2007 11:02AM
Anyone know how Networker even knows it's a VTL and it's physical disk
capacity? All the VTLs I've seen all emulate a known silo/autochanger.
This is really aggravating that EMC is tacking on a new charge without
adding any functionality.

Joel

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Stuart Whitby
Sent: Thursday, August 16, 2007 10:00 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Depending on the VTL involved, it will manage the cloning of data to
physical tape. If this is license-free, then it may be better to do
this than to involve NetWorker, which will require a further jukebox
license to cover this. The way it works on a CDL is that the CDL
controls the physical library, and will load tapes and route the data to
NetWorker that way. Or so I believe - didn't have physical libraries on
my last job :)

Cheers,

Stuart.

________________________________

From: EMC NetWorker discussion on behalf of mark wragge
Sent: Thu 16/08/2007 11:39
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Does this mean that there is a way to stage data from a VTL to physical
tape? Is this controlled from networker administrator staging OR from
the VTL administration software?

At the moment we are cloning from VTL to physical and then re-labeling
the VTL tape to free up space. is there a better way requiring less
manul intervention to free up disk space (assuming that retention
periods cannot be changed).

Thanks again for all these tips.

Dag Nygren <dag < at > NEWTECH.FI> wrote:
[quote]Essentially you can get disk to disk backup speeds, and can do
[/quote]dynamic drive
[quote]sharing. Of course, you do loose the ability to read and write at the
[/quote]same
[quote]time, that you get from an advanced file type device.
[/quote]
If you are into staging savesets around, you will also not free up space
until all the savesets on the tape have been staged...

I personally think that it is better to invest in more space for your
ATFD

Best
Dag

type "signoff networker" in the body of the email. Please write to
networker-request < at > listserv.temple.edu if you have any problems with this
list. You can access the archives at
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

Send instant messages to your online friends
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http://listserv.temple.edu/archives/networker.html or
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list. You can access the archives at
http://listserv.temple.edu/archives/networker.html or
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new to Virtual Tape Library - what are the benefits?
August 16, 2007 12:10PM
The problem with letting the CDL handle staging to physical tape is a
matter of tape usage and capacity. Since the compression ratio you'll
get on physical tape is dependent on the data being written, it can't be
reliably predicted. So when the EMC CDL creates virtual tapes it limits
them to a pre-determined size (which you can change). By default CDLs
do not compress the data they write to the virtual tape, which is good
because of the huge performance penalty they take when compressing data.

As an example, say you have LTO-3 tapes, with 400 GB native/~800GB
compressed capacity. If you emulate LTO-3 tapes in the CDL it will
default to 400 GB capacity, which is not compressed in any way. When
the CDL migrates data to a directly attached physical library, it does
it on a volume by volume basis. So your 400 GB of data on a virtual
tape will be migrated to a physical LTO-3 tape which will compress in
hardware. You will end up filling only ~50-60% of that physical tape.
You can force the virtual tapes to larger sizes to try to compensate, at
the risk of data migration failing because a particular virtual volume's
data will not compress as well as you have predicted. You save an
autochanger license, but use twice as much physical tape. You save on
the licensing and support costs, but pay more for media and extra time
spent shuffling tapes.

It's a trade-off. I prefer to run the CDL and the physical autochanger
side-by-side. You have to license them both, but you gain the ability
to fully use your physical media by cloning/staging in Networker, which
is saveset-based. In addition, you can always run some backups directly
to physical tape which you couldn't do if the physical autochanger was
hidden behind the CDL.

YMMV. I can only speak from experience with CDLs, other VTLs may
differ. I haven't gotten a chance to play with the latest CDLs yet, so
I don't know what EMC might have done regarding this issue.

Andy

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Stuart Whitby
Sent: Thursday, August 16, 2007 10:00 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Depending on the VTL involved, it will manage the cloning of data to
physical tape. If this is license-free, then it may be better to do
this than to involve NetWorker, which will require a further jukebox
license to cover this. The way it works on a CDL is that the CDL
controls the physical library, and will load tapes and route the data to
NetWorker that way. Or so I believe - didn't have physical libraries on
my last job :)

Cheers,

Stuart.

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 16, 2007 12:19PM
Or, even worse, sometimes the compression on the CDL is better than it is ont your tape, so if you leave the default size, when you go to export your VTs to tape, they dont fit, and the export will fail.

I have used the EMC CDLs for a while now, and exports are the single biggest problem. I would definately agree with Andy, you are much better running them in parallel, rather than letting the CDL pretend that it is a physical tape library. If I had to do it over again, I would much rather let Networker manage my staging and not the CDL because those exports are unbearably slow sometimes.

Kelly

----- Original Message ----
From: Andrew Quintana <Andrew.Quintana < at > WPNI.COM>
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Sent: Thursday, August 16, 2007 2:10:14 PM
Subject: Re: [Networker] new to Virtual Tape Library - what are the benefits?

The problem with letting the CDL handle staging to physical tape is a
matter of tape usage and capacity. Since the compression ratio you'll
get on physical tape is dependent on the data being written, it can't be
reliably predicted. So when the EMC CDL creates virtual tapes it limits
them to a pre-determined size (which you can change). By default CDLs
do not compress the data they write to the virtual tape, which is good
because of the huge performance penalty they take when compressing data.

As an example, say you have LTO-3 tapes, with 400 GB native/~800GB
compressed capacity. If you emulate LTO-3 tapes in the CDL it will
default to 400 GB capacity, which is not compressed in any way. When
the CDL migrates data to a directly attached physical library, it does
it on a volume by volume basis. So your 400 GB of data on a virtual
tape will be migrated to a physical LTO-3 tape which will compress in
hardware. You will end up filling only ~50-60% of that physical tape.
You can force the virtual tapes to larger sizes to try to compensate, at
the risk of data migration failing because a particular virtual volume's
data will not compress as well as you have predicted. You save an
autochanger license, but use twice as much physical tape. You save on
the licensing and support costs, but pay more for media and extra time
spent shuffling tapes.

It's a trade-off. I prefer to run the CDL and the physical autochanger
side-by-side. You have to license them both, but you gain the ability
to fully use your physical media by cloning/staging in Networker, which
is saveset-based. In addition, you can always run some backups directly
to physical tape which you couldn't do if the physical autochanger was
hidden behind the CDL.

YMMV. I can only speak from experience with CDLs, other VTLs may
differ. I haven't gotten a chance to play with the latest CDLs yet, so
I don't know what EMC might have done regarding this issue.

Andy

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Stuart Whitby
Sent: Thursday, August 16, 2007 10:00 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Depending on the VTL involved, it will manage the cloning of data to
physical tape. If this is license-free, then it may be better to do
this than to involve NetWorker, which will require a further jukebox
license to cover this. The way it works on a CDL is that the CDL
controls the physical library, and will load tapes and route the data to
NetWorker that way. Or so I believe - didn't have physical libraries on
my last job :)

Cheers,

Stuart.

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

____________________________________________________________________________________
Boardwalk for $500? In 2007? Ha! Play Monopoly Here and Now (it's updated for today's economy) at Yahoo! Games.
http://get.games.yahoo.com/proddesc?gamekey=monopolyherenow

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 16, 2007 04:41PM
[quote]Depending on the VTL involved, it will manage the cloning of data to physical tape. If this is license-free, then it may be better to do this than to involve NetWorker, which will require a further jukebox license to cover this. The way it works on a CDL is that the CDL controls the physical library, and will load tapes and route the data to NetWorker that way. Or so I believe - didn't have physical libraries on my last job :)
[/quote]
Well...
You need two GUI:s to control this process, which is not very nice.
Additionally Networker looses control over the tape after it is cloned to
physical. No automatic loading etc.

And you cannot stage individual savesets, but it is the whole tape
or nothing

I am still not convinced ;-)

Dag

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 17, 2007 06:39AM
We have a few VTLs from various vendors and heavy use of ATFD devices.

We have had issues on all the VTLs - vendor issues aside, the problem is
mostly emulating a jukebox with something that isnt a jukebox. Sure,
you get speed and some management benefits, but in my view the jukebox
emulation causes more problems that it solves. Mostly in the area of
"volume" management - if you dont plan it right you can end up with a
VTL full of volumes you cant expire because they keep getting little
backups appended to them.

Basically our approach is to create many smaller virtual tapes, so once
they fill up they can sit there and be expired later on. If you have
too big a tape size they tend to be appended to longer and take longer
to expire, so your VTL capacity gets eaten up. Maybe its just the
vendor we have for one product, but I also dont trust deduplication yet
- I have seen performance issues as the VTL filled up and trying to read
it back.

Personally, I think AFTD is a better approach if you dont plan on
directly zoning the VTL to many machines and are mostly backing up over
the network. Its simple to manage (depending on what networker bug you
are hitting that week) and is easier to expand and observe. With good
storage and physical tape to clone it generally just works.

mark wragge wrote:
[quote]Hi, I am new to the use of VTL (clariion disk) and I would like to know what the benefits of using the VTL are over using Advanced Disk Device.
Also, is there such thing as staging on a VTL? If not then what is the best way to free up disk space when it is full - is it cloning to tape and then re-labeling the virtual media.

Any examples of how you are using VTL and managing the media would be appreciated.

Regards, Mark

Send instant messages to your online friends http://uk.messenger.yahoo.com

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
[/quote]

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new to Virtual Tape Library - what are the benefits?
August 17, 2007 06:40AM
We trialed a Netapps VTL - I didnt use it, but the reports from the guys
who used it (and know their stuff) was that the Netapps virtual to
physical staging "just worked" - very hands off and reliable.

Andrew Quintana wrote:
[quote]The problem with letting the CDL handle staging to physical tape is a
matter of tape usage and capacity. Since the compression ratio you'll
get on physical tape is dependent on the data being written, it can't be
reliably predicted. So when the EMC CDL creates virtual tapes it limits
them to a pre-determined size (which you can change). By default CDLs
do not compress the data they write to the virtual tape, which is good
because of the huge performance penalty they take when compressing data.

As an example, say you have LTO-3 tapes, with 400 GB native/~800GB
compressed capacity. If you emulate LTO-3 tapes in the CDL it will
default to 400 GB capacity, which is not compressed in any way. When
the CDL migrates data to a directly attached physical library, it does
it on a volume by volume basis. So your 400 GB of data on a virtual
tape will be migrated to a physical LTO-3 tape which will compress in
hardware. You will end up filling only ~50-60% of that physical tape.
You can force the virtual tapes to larger sizes to try to compensate, at
the risk of data migration failing because a particular virtual volume's
data will not compress as well as you have predicted. You save an
autochanger license, but use twice as much physical tape. You save on
the licensing and support costs, but pay more for media and extra time
spent shuffling tapes.

It's a trade-off. I prefer to run the CDL and the physical autochanger
side-by-side. You have to license them both, but you gain the ability
to fully use your physical media by cloning/staging in Networker, which
is saveset-based. In addition, you can always run some backups directly
to physical tape which you couldn't do if the physical autochanger was
hidden behind the CDL.

YMMV. I can only speak from experience with CDLs, other VTLs may
differ. I haven't gotten a chance to play with the latest CDLs yet, so
I don't know what EMC might have done regarding this issue.

Andy

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Stuart Whitby
Sent: Thursday, August 16, 2007 10:00 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Depending on the VTL involved, it will manage the cloning of data to
physical tape. If this is license-free, then it may be better to do
this than to involve NetWorker, which will require a further jukebox
license to cover this. The way it works on a CDL is that the CDL
controls the physical library, and will load tapes and route the data to
NetWorker that way. Or so I believe - didn't have physical libraries on
my last job :)

Cheers,

Stuart.

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
[/quote]

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 17, 2007 09:38AM
We will aguire Netapp VTL, supports Tape smart sizing to fill the tape
appropriatly, also supports Hardware Compresion, didup is on it's way.
Can you detail your cloning process for our benefit with scirpt expamples,
what do you do to expire tapes on VTL, how do you maximize the use of
avallble disk space on VTL to as to retain maximum data.

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 17, 2007 12:02PM
[quote]We trialed a Netapps VTL - I didnt use it, but the reports from the guys
who used it (and know their stuff) was that the Netapps virtual to
physical staging "just worked" - very hands off and reliable.
[/quote]
Done any recovers from the off-staged tapes recently??

Best
Dag

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 18, 2007 08:17AM
Not sure - the guys doing the work did a very thorough job and knew
what they had to test they put in a lot of hours to test a number of
VTLs. I am sure bringing back from tape staged offsite would have been
part of it, and all indications were that it worked well.

Senior management hamstrung the project by changing direction at the
last minute and it has not gone past a proof of concept stage, so no
real production results to speak of.

Dag Nygren wrote:
[quote][quote]We trialed a Netapps VTL - I didnt use it, but the reports from the guys
who used it (and know their stuff) was that the Netapps virtual to
physical staging "just worked" - very hands off and reliable.
[/quote]

Done any recovers from the off-staged tapes recently??

Best
Dag
[/quote]

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 22, 2007 10:46AM
I was a bit rash in making this judgment... there are some added
benefits of the VTL license. Particularly being able to access
multiple(starts with 3) VTL instances on one VTL 'frame' with one
license. Sorry EMC.

Extracting foot from mouth.

I'm assuming an autochange license will still work with a VTL in 7.4,
anyone tested this? We may have to do this until I can budget for a VTL
license. But I hate to be unable to upgrade because of this.

Joel

-----Original Message-----
From: Joel Fisher
Sent: Thursday, August 16, 2007 2:03 PM
To: 'EMC NetWorker discussion'; 'Stuart Whitby'
Subject: RE: [Networker] new to Virtual Tape Library - what are the
benefits?

Anyone know how Networker even knows it's a VTL and it's physical disk
capacity? All the VTLs I've seen all emulate a known silo/autochanger.
This is really aggravating that EMC is tacking on a new charge without
adding any functionality.

Joel

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Stuart Whitby
Sent: Thursday, August 16, 2007 10:00 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Depending on the VTL involved, it will manage the cloning of data to
physical tape. If this is license-free, then it may be better to do
this than to involve NetWorker, which will require a further jukebox
license to cover this. The way it works on a CDL is that the CDL
controls the physical library, and will load tapes and route the data to
NetWorker that way. Or so I believe - didn't have physical libraries on
my last job :)

Cheers,

Stuart.

________________________________

From: EMC NetWorker discussion on behalf of mark wragge
Sent: Thu 16/08/2007 11:39
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Does this mean that there is a way to stage data from a VTL to physical
tape? Is this controlled from networker administrator staging OR from
the VTL administration software?

At the moment we are cloning from VTL to physical and then re-labeling
the VTL tape to free up space. is there a better way requiring less
manul intervention to free up disk space (assuming that retention
periods cannot be changed).

Thanks again for all these tips.

Dag Nygren <dag < at > NEWTECH.FI> wrote:
[quote]Essentially you can get disk to disk backup speeds, and can do
[/quote]dynamic drive
[quote]sharing. Of course, you do loose the ability to read and write at the
[/quote]same
[quote]time, that you get from an advanced file type device.
[/quote]
If you are into staging savesets around, you will also not free up space
until all the savesets on the tape have been staged...

I personally think that it is better to invest in more space for your
ATFD

Best
Dag

type "signoff networker" in the body of the email. Please write to
networker-request < at > listserv.temple.edu if you have any problems with this
list. You can access the archives at
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

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list. You can access the archives at
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via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 22, 2007 02:49PM
The question is a very important one. Are you REQUIRED to buy the VTL
license (even if you have valid tape drive licenses?), or are you
ALLOWED to buy the VTL license if you want the extra VTL functionality?
Symantec has gone the former, not the latter (me not happy), so it will
be interesting to see what EMC does.

---
W. Curtis Preston
Backup Blog < at > www.backupcentral.com
VP Data Protection, GlassHouse Technologies

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Joel Fisher
Sent: Wednesday, August 22, 2007 10:47 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

I was a bit rash in making this judgment... there are some added
benefits of the VTL license. Particularly being able to access
multiple(starts with 3) VTL instances on one VTL 'frame' with one
license. Sorry EMC.

Extracting foot from mouth.

I'm assuming an autochange license will still work with a VTL in 7.4,
anyone tested this? We may have to do this until I can budget for a VTL
license. But I hate to be unable to upgrade because of this.

Joel

-----Original Message-----
From: Joel Fisher
Sent: Thursday, August 16, 2007 2:03 PM
To: 'EMC NetWorker discussion'; 'Stuart Whitby'
Subject: RE: [Networker] new to Virtual Tape Library - what are the
benefits?

Anyone know how Networker even knows it's a VTL and it's physical disk
capacity? All the VTLs I've seen all emulate a known silo/autochanger.
This is really aggravating that EMC is tacking on a new charge without
adding any functionality.

Joel

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Stuart Whitby
Sent: Thursday, August 16, 2007 10:00 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Depending on the VTL involved, it will manage the cloning of data to
physical tape. If this is license-free, then it may be better to do
this than to involve NetWorker, which will require a further jukebox
license to cover this. The way it works on a CDL is that the CDL
controls the physical library, and will load tapes and route the data to
NetWorker that way. Or so I believe - didn't have physical libraries on
my last job :)

Cheers,

Stuart.

________________________________

From: EMC NetWorker discussion on behalf of mark wragge
Sent: Thu 16/08/2007 11:39
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Does this mean that there is a way to stage data from a VTL to physical
tape? Is this controlled from networker administrator staging OR from
the VTL administration software?

At the moment we are cloning from VTL to physical and then re-labeling
the VTL tape to free up space. is there a better way requiring less
manul intervention to free up disk space (assuming that retention
periods cannot be changed).

Thanks again for all these tips.

Dag Nygren <dag < at > NEWTECH.FI> wrote:
[quote]Essentially you can get disk to disk backup speeds, and can do
[/quote]dynamic drive
[quote]sharing. Of course, you do loose the ability to read and write at the
[/quote]same
[quote]time, that you get from an advanced file type device.
[/quote]
If you are into staging savesets around, you will also not free up space
until all the savesets on the tape have been staged...

I personally think that it is better to invest in more space for your
ATFD

Best
Dag

type "signoff networker" in the body of the email. Please write to
networker-request < at > listserv.temple.edu if you have any problems with this
list. You can access the archives at
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

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via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 22, 2007 03:24PM
While attending a NW 7.4 pre-release training session in the spring, the
EMC engineer stated specifically that existing autochanger licenses
would still be valid.

Curtis Preston wrote:

[quote]The question is a very important one. Are you REQUIRED to buy the VTL
license (even if you have valid tape drive licenses?), or are you
ALLOWED to buy the VTL license if you want the extra VTL functionality?
Symantec has gone the former, not the latter (me not happy), so it will
be interesting to see what EMC does.

---
W. Curtis Preston
Backup Blog < at > www.backupcentral.com
VP Data Protection, GlassHouse Technologies

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Joel Fisher
Sent: Wednesday, August 22, 2007 10:47 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

I was a bit rash in making this judgment... there are some added
benefits of the VTL license. Particularly being able to access
multiple(starts with 3) VTL instances on one VTL 'frame' with one
license. Sorry EMC.

Extracting foot from mouth.

I'm assuming an autochange license will still work with a VTL in 7.4,
anyone tested this? We may have to do this until I can budget for a VTL
license. But I hate to be unable to upgrade because of this.

Joel

-----Original Message-----
From: Joel Fisher
Sent: Thursday, August 16, 2007 2:03 PM
To: 'EMC NetWorker discussion'; 'Stuart Whitby'
Subject: RE: [Networker] new to Virtual Tape Library - what are the
benefits?

Anyone know how Networker even knows it's a VTL and it's physical disk
capacity? All the VTLs I've seen all emulate a known silo/autochanger.
This is really aggravating that EMC is tacking on a new charge without
adding any functionality.

Joel

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Stuart Whitby
Sent: Thursday, August 16, 2007 10:00 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Depending on the VTL involved, it will manage the cloning of data to
physical tape. If this is license-free, then it may be better to do
this than to involve NetWorker, which will require a further jukebox
license to cover this. The way it works on a CDL is that the CDL
controls the physical library, and will load tapes and route the data to
NetWorker that way. Or so I believe - didn't have physical libraries on
my last job :)

Cheers,

Stuart.

________________________________

From: EMC NetWorker discussion on behalf of mark wragge
Sent: Thu 16/08/2007 11:39
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Does this mean that there is a way to stage data from a VTL to physical
tape? Is this controlled from networker administrator staging OR from
the VTL administration software?

At the moment we are cloning from VTL to physical and then re-labeling
the VTL tape to free up space. is there a better way requiring less
manul intervention to free up disk space (assuming that retention
periods cannot be changed).

Thanks again for all these tips.

Dag Nygren <dag < at > NEWTECH.FI> wrote:
[quote]Essentially you can get disk to disk backup speeds, and can do
[/quote]dynamic drive

[quote]sharing. Of course, you do loose the ability to read and write at the

[/quote]same

[quote]time, that you get from an advanced file type device.

[/quote]
If you are into staging savesets around, you will also not free up space
until all the savesets on the tape have been staged...

I personally think that it is better to invest in more space for your
ATFD

Best
Dag

type "signoff networker" in the body of the email. Please write to
networker-request < at > listserv.temple.edu if you have any problems with this
list. You can access the archives at
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

Send instant messages to your online friends
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type "signoff networker" in the body of the email. Please write to
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list. You can access the archives at
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type "signoff networker" in the body of the email. Please write to
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via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

[/quote]

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 22, 2007 03:52PM
Unfortunatly, what an EMC engineer says and what reality are do not
always coincide. ;) I hope that is the official answer, as most I know
do not want to be forced to buy the license just because they "changed
their tape drive vendor," in their view.

---
W. Curtis Preston
Backup Blog < at > www.backupcentral.com
VP Data Protection, GlassHouse Technologies

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Rick Brode
Sent: Wednesday, August 22, 2007 3:25 PM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

While attending a NW 7.4 pre-release training session in the spring, the

EMC engineer stated specifically that existing autochanger licenses
would still be valid.

Curtis Preston wrote:

[quote]The question is a very important one. Are you REQUIRED to buy the VTL
license (even if you have valid tape drive licenses?), or are you
ALLOWED to buy the VTL license if you want the extra VTL functionality?
Symantec has gone the former, not the latter (me not happy), so it will
be interesting to see what EMC does.

---
W. Curtis Preston
Backup Blog < at > www.backupcentral.com
VP Data Protection, GlassHouse Technologies

-----Original Message-----
From: EMC NetWorker discussion [mailto]
[/quote]On
[quote]Behalf Of Joel Fisher
Sent: Wednesday, August 22, 2007 10:47 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

I was a bit rash in making this judgment... there are some added
benefits of the VTL license. Particularly being able to access
multiple(starts with 3) VTL instances on one VTL 'frame' with one
license. Sorry EMC.

Extracting foot from mouth.

I'm assuming an autochange license will still work with a VTL in 7.4,
anyone tested this? We may have to do this until I can budget for a
[/quote]VTL
[quote]license. But I hate to be unable to upgrade because of this.

Joel

-----Original Message-----
From: Joel Fisher
Sent: Thursday, August 16, 2007 2:03 PM
To: 'EMC NetWorker discussion'; 'Stuart Whitby'
Subject: RE: [Networker] new to Virtual Tape Library - what are the
benefits?

Anyone know how Networker even knows it's a VTL and it's physical disk
capacity? All the VTLs I've seen all emulate a known silo/autochanger.
This is really aggravating that EMC is tacking on a new charge without
adding any functionality.

Joel

-----Original Message-----
From: EMC NetWorker discussion [mailto]
[/quote]On
[quote]Behalf Of Stuart Whitby
Sent: Thursday, August 16, 2007 10:00 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Depending on the VTL involved, it will manage the cloning of data to
physical tape. If this is license-free, then it may be better to do
this than to involve NetWorker, which will require a further jukebox
license to cover this. The way it works on a CDL is that the CDL
controls the physical library, and will load tapes and route the data
[/quote]to
[quote]NetWorker that way. Or so I believe - didn't have physical libraries
[/quote]on
[quote]my last job :)

Cheers,

Stuart.

________________________________

From: EMC NetWorker discussion on behalf of mark wragge
Sent: Thu 16/08/2007 11:39
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

Does this mean that there is a way to stage data from a VTL to physical
tape? Is this controlled from networker administrator staging OR from
the VTL administration software?

At the moment we are cloning from VTL to physical and then
[/quote]re-labeling
[quote]the VTL tape to free up space. is there a better way requiring less
manul intervention to free up disk space (assuming that retention
periods cannot be changed).

Thanks again for all these tips.

Dag Nygren <dag < at > NEWTECH.FI> wrote:
[quote]Essentially you can get disk to disk backup speeds, and can do
[/quote]dynamic drive

[quote]sharing. Of course, you do loose the ability to read and write at the

[/quote]same

[quote]time, that you get from an advanced file type device.

[/quote]
If you are into staging savesets around, you will also not free up
[/quote]space
[quote]until all the savesets on the tape have been staged...

I personally think that it is better to invest in more space for your
ATFD

Best
Dag

type "signoff networker" in the body of the email. Please write to
networker-request < at > listserv.temple.edu if you have any problems with
[/quote]this
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new to Virtual Tape Library - what are the benefits?
August 22, 2007 04:36PM
I've read this whole thread now and wanted to comment on it with a
little more thought...

I in favor of VTLs or other intelligent disk targets (IDTs). It's not
necessarily whether or not it's pretending to be tape; it's whether or
not it deals with the issues of using "regular" disk, which are:

1. Difficult to share between multiple storage nodes - must partition

2. When partitioning for multiple SNs, you have to decide how big to
make each slice.

3. 1:1 relationship between size of backups and size of disk (i.e. no
compression or de-dupe)

4. Fragmentation: users have reported issues with using filesystems as
targets for extended periods of time unless they're clearing the
filesystem every night.

IDTs remove with these issues:
1. Easy to share - with a VTL, use DDS in NW or just make multiple VTLs.
With a NAS IDT (Data Domain, NEC Hydrastor), just point a share at it.

2. Do not have to partition by storage node or even NetWorker server.
Whatever storage a SN uses, it uses.

3. Some have hardware compression and others have de-dupe. I've seen
it; it's real. And my opinion is that as long as you're also copying
everything to tape, I've got no issues with using de-dupe at this stage.

4. Fragmentation does not seem to be an issue as they use a MUCH larger
block size that's better suited to backups. Fragmentation issues have
also not been reported.

Issues:

1. There is the issue with managing migration to tape. With NetWorker,
there are easy ways and hard ways.

With disk/AFTD, you would use the disk staging facility in NW. It will
automatically stage backups to tape from disk, and delete de-staged
backups to make room for new babckups.

With an integrated VTL (like the EMC CDL, IBM, Sun, Falconstor, NetApp,
et al), you can have the CDL manage the migration. It sits between your
networker server and the physical tape library (PTL). It inventories
the PTL and represents to the NW server virtual tapes with the same
barcode and capacity as the real tapes. You back up to the fake tapes
and eject them. It then automatically copies them to physical tape.

If you don't like either of these options, the "hard way" is to script
your way into happiness. If you like this method, there's not much
difference between an AFTD and a VTL/IDT from a migration perspective.

2. There's also the issue where you can't expire a tape until all its
backups expire. This is no different than physical tape. I think this
is pretty easy to deal with. Either use really small virtual tapes or
mark your tapes as full with a script after each night's backups. A 400
GB tape marked full in a VTL won't take up 400 GB, so that's OK. That
way, each night's backups are on their own set of tapes, causing all of
them to be expired when those backups expire. (You also need to
segregate by retention period if this is to work well -- just like with
real tape.) You don't have this issue with an AFTD as it can expire
individual savesets, but I think that an AFTD comes with too many other
problems in large NW environments.

3. If you use an integrated VTL, there is the issue of matching virtual
to physical size. The big thing is that virtual tape MUST fit on the
physical tape. Some VTLs allow you to pick the point at which the
virtual tape is full. If you pick a size that's too big, you won't fit
onto the physical tape and you've got badness. I like the new feature
of "right sizing," where the VTL figures out when to stop by sampling
the data that's coming through and seeing how well it's compressing.

4. The license issue. As long as EMC makes it an option, it's not a new
license they're trying to force down your throat. It's an optional
license that allows you to configure your VTL any way you want (e.g.
number of slots, etc.). As long as you stick with the "real" license,
you're limited to what you paid for. Don't forget that AFTD costs
money, too!

I hope this helps.

---
W. Curtis Preston
Backup Blog < at > www.backupcentral.com
VP Data Protection, GlassHouse Technologies

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 22, 2007 04:52PM
[quote]1. There is the issue with managing migration to tape. With NetWorker,
there are easy ways and hard ways.

With disk/AFTD, you would use the disk staging facility in NW. It will
automatically stage backups to tape from disk, and delete de-staged
backups to make room for new babckups.

With an integrated VTL (like the EMC CDL, IBM, Sun, Falconstor, NetApp,
et al), you can have the CDL manage the migration. It sits between your
networker server and the physical tape library (PTL). It inventories
the PTL and represents to the NW server virtual tapes with the same
barcode and capacity as the real tapes. You back up to the fake tapes
and eject them. It then automatically copies them to physical tape.

If you don't like either of these options, the "hard way" is to script
your way into happiness. If you like this method, there's not much
difference between an AFTD and a VTL/IDT from a migration perspective.
[/quote]
Also, check on how the physical tape management is going to work in your
environment. I used a combo VTL about 3 years ago at a client. It had
it's uses, but one big problem with it was absolutely no CLI. They had
most of their tape motion scripted before it arrived, with email to colo
operators at remote locations. With the IDT, someone had to pull up a
web page and press buttons because the Networker/NetBackup "eject"
didn't eject a physical tape.

--
Darren Dunham ddunham < at > taos.com
Senior Technical Consultant TAOS http://www.taos.com/
Got some Dr Pepper? San Francisco, CA bay area
< This line left intentionally blank to confuse you. >

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 23, 2007 03:35AM
Thanks very much, Curtis, for an excellent summary. It will be very helpful.

You touched on compression, but I still have questions. One vendor told us
that with most VTLs you can't use compression, because the VTL can't
compress identically the same as the drive will. You could end up with more
data on a virtual tape than will fit on the correspondnig physical tape and
therefore, in your words, "badness". The vendor's product, of course, worked
around this issue. How are real-world users addressing the situation?

Thanks again,

Conrad Macina
Pfizer, Inc.

On Wed, 22 Aug 2007 19:35:38 -0400, Curtis Preston <cpreston < at > GLASSHOUSE.COM>
wrote:

[quote]I've read this whole thread now and wanted to comment on it with a
little more thought...

I in favor of VTLs or other intelligent disk targets (IDTs). It's not
necessarily whether or not it's pretending to be tape; it's whether or
not it deals with the issues of using "regular" disk, which are:

1. Difficult to share between multiple storage nodes - must partition

2. When partitioning for multiple SNs, you have to decide how big to
make each slice.

3. 1:1 relationship between size of backups and size of disk (i.e. no
compression or de-dupe)

4. Fragmentation: users have reported issues with using filesystems as
targets for extended periods of time unless they're clearing the
filesystem every night.

IDTs remove with these issues:
1. Easy to share - with a VTL, use DDS in NW or just make multiple VTLs.
With a NAS IDT (Data Domain, NEC Hydrastor), just point a share at it.

2. Do not have to partition by storage node or even NetWorker server.
Whatever storage a SN uses, it uses.

3. Some have hardware compression and others have de-dupe. I've seen
it; it's real. And my opinion is that as long as you're also copying
everything to tape, I've got no issues with using de-dupe at this stage.

4. Fragmentation does not seem to be an issue as they use a MUCH larger
block size that's better suited to backups. Fragmentation issues have
also not been reported.

Issues:

1. There is the issue with managing migration to tape. With NetWorker,
there are easy ways and hard ways.

With disk/AFTD, you would use the disk staging facility in NW. It will
automatically stage backups to tape from disk, and delete de-staged
backups to make room for new babckups.

With an integrated VTL (like the EMC CDL, IBM, Sun, Falconstor, NetApp,
et al), you can have the CDL manage the migration. It sits between your
networker server and the physical tape library (PTL). It inventories
the PTL and represents to the NW server virtual tapes with the same
barcode and capacity as the real tapes. You back up to the fake tapes
and eject them. It then automatically copies them to physical tape.

If you don't like either of these options, the "hard way" is to script
your way into happiness. If you like this method, there's not much
difference between an AFTD and a VTL/IDT from a migration perspective.

2. There's also the issue where you can't expire a tape until all its
backups expire. This is no different than physical tape. I think this
is pretty easy to deal with. Either use really small virtual tapes or
mark your tapes as full with a script after each night's backups. A 400
GB tape marked full in a VTL won't take up 400 GB, so that's OK. That
way, each night's backups are on their own set of tapes, causing all of
them to be expired when those backups expire. (You also need to
segregate by retention period if this is to work well -- just like with
real tape.) You don't have this issue with an AFTD as it can expire
individual savesets, but I think that an AFTD comes with too many other
problems in large NW environments.

3. If you use an integrated VTL, there is the issue of matching virtual
to physical size. The big thing is that virtual tape MUST fit on the
physical tape. Some VTLs allow you to pick the point at which the
virtual tape is full. If you pick a size that's too big, you won't fit
onto the physical tape and you've got badness. I like the new feature
of "right sizing," where the VTL figures out when to stop by sampling
the data that's coming through and seeing how well it's compressing.

4. The license issue. As long as EMC makes it an option, it's not a new
license they're trying to force down your throat. It's an optional
license that allows you to configure your VTL any way you want (e.g.
number of slots, etc.). As long as you stick with the "real" license,
you're limited to what you paid for. Don't forget that AFTD costs
money, too!

I hope this helps.

---
W. Curtis Preston
Backup Blog < at > www.backupcentral.com
VP Data Protection, GlassHouse Technologies

[/quote]"signoff networker" in the body of the email. Please write to
networker-request < at > listserv.temple.edu if you have any problems with this
list. You can access the archives at
http://listserv.temple.edu/archives/networker.html or
[quote]via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
=========================================================================
[/quote]

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 23, 2007 03:57AM
This has been a great thread with excellent feedback.

One thing i am still unsure of is if it is possible to multistream to a virtual tape device. Is the target sessions setting on the virtual tape device relevant and will it accept more than one stream at a time?

Curtis Preston <cpreston < at > GLASSHOUSE.COM> wrote:
I've read this whole thread now and wanted to comment on it with a
little more thought...

I in favor of VTLs or other intelligent disk targets (IDTs). It's not
necessarily whether or not it's pretending to be tape; it's whether or
not it deals with the issues of using "regular" disk, which are:

1. Difficult to share between multiple storage nodes - must partition

2. When partitioning for multiple SNs, you have to decide how big to
make each slice.

3. 1:1 relationship between size of backups and size of disk (i.e. no
compression or de-dupe)

4. Fragmentation: users have reported issues with using filesystems as
targets for extended periods of time unless they're clearing the
filesystem every night.

IDTs remove with these issues:
1. Easy to share - with a VTL, use DDS in NW or just make multiple VTLs.
With a NAS IDT (Data Domain, NEC Hydrastor), just point a share at it.

2. Do not have to partition by storage node or even NetWorker server.
Whatever storage a SN uses, it uses.

3. Some have hardware compression and others have de-dupe. I've seen
it; it's real. And my opinion is that as long as you're also copying
everything to tape, I've got no issues with using de-dupe at this stage.

4. Fragmentation does not seem to be an issue as they use a MUCH larger
block size that's better suited to backups. Fragmentation issues have
also not been reported.

Issues:

1. There is the issue with managing migration to tape. With NetWorker,
there are easy ways and hard ways.

With disk/AFTD, you would use the disk staging facility in NW. It will
automatically stage backups to tape from disk, and delete de-staged
backups to make room for new babckups.

With an integrated VTL (like the EMC CDL, IBM, Sun, Falconstor, NetApp,
et al), you can have the CDL manage the migration. It sits between your
networker server and the physical tape library (PTL). It inventories
the PTL and represents to the NW server virtual tapes with the same
barcode and capacity as the real tapes. You back up to the fake tapes
and eject them. It then automatically copies them to physical tape.

If you don't like either of these options, the "hard way" is to script
your way into happiness. If you like this method, there's not much
difference between an AFTD and a VTL/IDT from a migration perspective.

2. There's also the issue where you can't expire a tape until all its
backups expire. This is no different than physical tape. I think this
is pretty easy to deal with. Either use really small virtual tapes or
mark your tapes as full with a script after each night's backups. A 400
GB tape marked full in a VTL won't take up 400 GB, so that's OK. That
way, each night's backups are on their own set of tapes, causing all of
them to be expired when those backups expire. (You also need to
segregate by retention period if this is to work well -- just like with
real tape.) You don't have this issue with an AFTD as it can expire
individual savesets, but I think that an AFTD comes with too many other
problems in large NW environments.

3. If you use an integrated VTL, there is the issue of matching virtual
to physical size. The big thing is that virtual tape MUST fit on the
physical tape. Some VTLs allow you to pick the point at which the
virtual tape is full. If you pick a size that's too big, you won't fit
onto the physical tape and you've got badness. I like the new feature
of "right sizing," where the VTL figures out when to stop by sampling
the data that's coming through and seeing how well it's compressing.

4. The license issue. As long as EMC makes it an option, it's not a new
license they're trying to force down your throat. It's an optional
license that allows you to configure your VTL any way you want (e.g.
number of slots, etc.). As long as you stick with the "real" license,
you're limited to what you paid for. Don't forget that AFTD costs
money, too!

I hope this helps.

---
W. Curtis Preston
Backup Blog < at > www.backupcentral.com
VP Data Protection, GlassHouse Technologies

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

Send instant messages to your online friends http://uk.messenger.yahoo.com

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 23, 2007 04:46AM
The one thing that has to be remembered is that Networker does not
comprehend a VTL as anything other than another tape library.
Therefore, you most cetainly can multistream data to a VTL device, you
can change (and have an affect) the number of target sessions for a VTL
device. The bottom line: whatever you can do to a 'real' tapedrive,
you can do to a VTL tapedrive. It's a tough concept to wrap your arms
around, but if you come to grips with it now, then it will help in the
future.

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of mark wragge
Sent: Thursday, August 23, 2007 6:58 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

This has been a great thread with excellent feedback.

One thing i am still unsure of is if it is possible to multistream to
a virtual tape device. Is the target sessions setting on the virtual
tape device relevant and will it accept more than one stream at a time?

Curtis Preston <cpreston < at > GLASSHOUSE.COM> wrote:
I've read this whole thread now and wanted to comment on it with a
little more thought...

I in favor of VTLs or other intelligent disk targets (IDTs). It's not
necessarily whether or not it's pretending to be tape; it's whether or
not it deals with the issues of using "regular" disk, which are:

1. Difficult to share between multiple storage nodes - must partition

2. When partitioning for multiple SNs, you have to decide how big to
make each slice.

3. 1:1 relationship between size of backups and size of disk (i.e. no
compression or de-dupe)

4. Fragmentation: users have reported issues with using filesystems as
targets for extended periods of time unless they're clearing the
filesystem every night.

IDTs remove with these issues:
1. Easy to share - with a VTL, use DDS in NW or just make multiple VTLs.
With a NAS IDT (Data Domain, NEC Hydrastor), just point a share at it.

2. Do not have to partition by storage node or even NetWorker server.
Whatever storage a SN uses, it uses.

3. Some have hardware compression and others have de-dupe. I've seen it;
it's real. And my opinion is that as long as you're also copying
everything to tape, I've got no issues with using de-dupe at this stage.

4. Fragmentation does not seem to be an issue as they use a MUCH larger
block size that's better suited to backups. Fragmentation issues have
also not been reported.

Issues:

1. There is the issue with managing migration to tape. With NetWorker,
there are easy ways and hard ways.

With disk/AFTD, you would use the disk staging facility in NW. It will
automatically stage backups to tape from disk, and delete de-staged
backups to make room for new babckups.

With an integrated VTL (like the EMC CDL, IBM, Sun, Falconstor, NetApp,
et al), you can have the CDL manage the migration. It sits between your
networker server and the physical tape library (PTL). It inventories the
PTL and represents to the NW server virtual tapes with the same barcode
and capacity as the real tapes. You back up to the fake tapes and eject
them. It then automatically copies them to physical tape.

If you don't like either of these options, the "hard way" is to script
your way into happiness. If you like this method, there's not much
difference between an AFTD and a VTL/IDT from a migration perspective.

2. There's also the issue where you can't expire a tape until all its
backups expire. This is no different than physical tape. I think this is
pretty easy to deal with. Either use really small virtual tapes or mark
your tapes as full with a script after each night's backups. A 400 GB
tape marked full in a VTL won't take up 400 GB, so that's OK. That way,
each night's backups are on their own set of tapes, causing all of them
to be expired when those backups expire. (You also need to segregate by
retention period if this is to work well -- just like with real tape.)
You don't have this issue with an AFTD as it can expire individual
savesets, but I think that an AFTD comes with too many other problems in
large NW environments.

3. If you use an integrated VTL, there is the issue of matching virtual
to physical size. The big thing is that virtual tape MUST fit on the
physical tape. Some VTLs allow you to pick the point at which the
virtual tape is full. If you pick a size that's too big, you won't fit
onto the physical tape and you've got badness. I like the new feature of
"right sizing," where the VTL figures out when to stop by sampling the
data that's coming through and seeing how well it's compressing.

4. The license issue. As long as EMC makes it an option, it's not a new
license they're trying to force down your throat. It's an optional
license that allows you to configure your VTL any way you want (e.g.
number of slots, etc.). As long as you stick with the "real" license,
you're limited to what you paid for. Don't forget that AFTD costs money,
too!

I hope this helps.

---
W. Curtis Preston
Backup Blog < at > www.backupcentral.com
VP Data Protection, GlassHouse Technologies

type "signoff networker" in the body of the email. Please write to
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list. You can access the archives at
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Send instant messages to your online friends
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new to Virtual Tape Library - what are the benefits?
August 23, 2007 05:27AM
Curtis,

Could you comment on what you see is the problems with AFTD in large NW
environments? You mentioned them in this item, but don't go into
detail.

Thanks.
Teresa

-----Original Message-----
From: EMC NetWorker discussion [mailto] On
Behalf Of Curtis Preston
Sent: Wednesday, August 22, 2007 7:36 PM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what are the
benefits?

I've read this whole thread now and wanted to comment on it with a
little more thought...

.
.
.
2. There's also the issue where you can't expire a tape until all its
backups expire. This is no different than physical tape. I think this
is pretty easy to deal with. Either use really small virtual tapes or
mark your tapes as full with a script after each night's backups. A 400
GB tape marked full in a VTL won't take up 400 GB, so that's OK. That
way, each night's backups are on their own set of tapes, causing all of
them to be expired when those backups expire. (You also need to
segregate by retention period if this is to work well -- just like with
real tape.) You don't have this issue with an AFTD as it can expire
individual savesets, but I think that an AFTD comes with too many other
problems in large NW environments.

via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
new to Virtual Tape Library - what are the benefits?
August 23, 2007 05:35AM
Having had a brush with VTLs over the summer I have a couple of comments
on the thread.

The virtual tape size and physical tape size is a real issue, the VTL
(at least the one I was playing with) had no way of getting out of this
so we had to use nsrstage to the same pool after adjusting the max size.

Virtual tapes can get corrupt (for one reason or another). Once again,
the VTL didn't come with any tools like we have with Networker (we can
use nsrck to fix various problems with client index but there is no
equivalent consistency checker for virtual volumes). Same thing with the
metadata (which should be a straight forward job to recreate). (nsrstage
to the rescue again...)

It is possible to get volume and barcode mismatch on Networker but the
VTL reports both the same (makes sense if you can grasp the idea that
the VTL is just a tape library to Networker) - as an aside this was
caused by drive mapping changes on a Windows box (rearranged the order
of the drives and so Networker loaded a tape in one drive and labelled
it with the barcode from another. VTL being blissfully unaware of this
exported the tape to a physical tape. Restore calls for tape (by volume)
VTL doesn't recognise it - have to manually load the barcode that
Networker has for that volume in order for it to work (nsrstage to the
rescue again...)

They do appear to be pretty versatile (the ability to replicate from VTL
to VTL makes offsiting data a breeze) but the supporting software
utilities have a way to go yet.

And, as with anything that uses disk, when estimating how much you'll
need, double your estimate (and then add some more). You'll need it.

Personally, I prefer the AFTD approach (been working well for us for
years - once you get round the idea that Networker will not straddle
devices so you need to make sure a saveset will fit). Oh yes, and the
multiple reads are a bonus that I didn't see with the VTL.

Regards
Bob

[quote]-----Original Message-----
From: EMC NetWorker discussion
[mailto] On Behalf Of Kantor, Adam
Sent: 23 August 2007 12:43
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what
are the benefits?

The one thing that has to be remembered is that Networker does
not comprehend a VTL as anything other than another tape library.
Therefore, you most cetainly can multistream data to a VTL
device, you can change (and have an affect) the number of
target sessions for a VTL device. The bottom line: whatever
you can do to a 'real' tapedrive, you can do to a VTL
tapedrive. It's a tough concept to wrap your arms around, but
if you come to grips with it now, then it will help in the future.

-----Original Message-----
From: EMC NetWorker discussion
[mailto] On Behalf Of mark wragge
Sent: Thursday, August 23, 2007 6:58 AM
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] new to Virtual Tape Library - what
are the benefits?

This has been a great thread with excellent feedback.

One thing i am still unsure of is if it is possible to
multistream to a virtual tape device. Is the target sessions
setting on the virtual tape device relevant and will it accept
more than one stream at a time?

Curtis Preston <cpreston < at > GLASSHOUSE.COM> wrote:
I've read this whole thread now and wanted to comment on it
with a little more thought...

I in favor of VTLs or other intelligent disk targets (IDTs).
It's not necessarily whether or not it's pretending to be
tape; it's whether or not it deals with the issues of using
"regular" disk, which are:

1. Difficult to share between multiple storage nodes - must partition

2. When partitioning for multiple SNs, you have to decide how
big to make each slice.

3. 1:1 relationship between size of backups and size of disk
(i.e. no compression or de-dupe)

4. Fragmentation: users have reported issues with using
filesystems as targets for extended periods of time unless
they're clearing the filesystem every night.

IDTs remove with these issues:
1. Easy to share - with a VTL, use DDS in NW or just make
multiple VTLs.
With a NAS IDT (Data Domain, NEC Hydrastor), just point a share at it.

2. Do not have to partition by storage node or even NetWorker server.
Whatever storage a SN uses, it uses.

3. Some have hardware compression and others have de-dupe.
I've seen it; it's real. And my opinion is that as long as
you're also copying everything to tape, I've got no issues
with using de-dupe at this stage.

4. Fragmentation does not seem to be an issue as they use a
MUCH larger block size that's better suited to backups.
Fragmentation issues have also not been reported.

Issues:

1. There is the issue with managing migration to tape. With
NetWorker, there are easy ways and hard ways.

With disk/AFTD, you would use the disk staging facility in NW.
It will automatically stage backups to tape from disk, and
delete de-staged backups to make room for new babckups.

With an integrated VTL (like the EMC CDL, IBM, Sun,
Falconstor, NetApp, et al), you can have the CDL manage the
migration. It sits between your networker server and the
physical tape library (PTL). It inventories the PTL and
represents to the NW server virtual tapes with the same
barcode and capacity as the real tapes. You back up to the
fake tapes and eject them. It then automatically copies them
to physical tape.

If you don't like either of these options, the "hard way" is
to script your way into happiness. If you like this method,
there's not much difference between an AFTD and a VTL/IDT from
a migration perspective.

2. There's also the issue where you can't expire a tape until
all its backups expire. This is no different than physical
tape. I think this is pretty easy to deal with. Either use
really small virtual tapes or mark your tapes as full with a
script after each night's backups. A 400 GB tape marked full
in a VTL won't take up 400 GB, so that's OK. That way, each
night's backups are on their own set of tapes, causing all of
them to be expired when those backups expire. (You also need
to segregate by retention period if this is to work well --
just like with real tape.) You don't have this issue with an
AFTD as it can expire individual savesets, but I think that an
AFTD comes with too many other problems in large NW environments.

3. If you use an integrated VTL, there is the issue of
matching virtual to physical size. The big thing is that
virtual tape MUST fit on the physical tape. Some VTLs allow
you to pick the point at which the virtual tape is full. If
you pick a size that's too big, you won't fit onto the
physical tape and you've got badness. I like the new feature
of "right sizing," where the VTL figures out when to stop by
sampling the data that's coming through and seeing how well
it's compressing.

4. The license issue. As long as EMC makes it an option, it's
not a new license they're trying to force down your throat.
It's an optional license that allows you to configure your VTL
any way you want (e.g.
number of slots, etc.). As long as you stick with the "real"
license, you're limited to what you paid for. Don't forget
that AFTD costs money, too!

I hope this helps.

---
W. Curtis Preston
Backup Blog < at > www.backupcentral.com
VP Data Protection, GlassHouse Technologies

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new to Virtual Tape Library - what are the benefits?
August 23, 2007 07:52AM
[quote]One thing i am still unsure of is if it is possible to multistream
to a virtual tape device. Is the target sessions setting on the
virtual tape device relevant and will it accept more than one stream
at a time?
[/quote]
Sure. Multiplexing data streams onto a single device is part of the
backup software doings, not an ability of the drive itself.

The question is, why would you want to?

The usual reason to multiplex onto a drive is that tape drives are
expensive so you can't buy as many as you need, and they perform better
at the top end of their bandwidth so you'd rather have multiple slow
clients feeding one drive.

This shouldn't be as true for VTLs. Most will let you create more
virtual devices inexpensively, and since you're feeding a disk, it
should react well when fed data at any speed. This gives you the
advantage of segregating your data before restore. In just about any
situation I can think of, you would not want to multiplex onto virtual
tape volumes.
--
Darren Dunham ddunham < at > taos.com
Senior Technical Consultant TAOS http://www.taos.com/
Got some Dr Pepper? San Francisco, CA bay area
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