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NW 8.x and LTO-7: is it about the drive or the tape?

Posted by marki 
Hey,

Hardware compatibility matrix indicates latest NW 8.2 compatibility is
LTO-7.

Does the actual tape format or the drive matter here? I.e. does it mean
that it requires an LTO-7 (or less) _drive_ or is an LTO-7 _tape_ in an
LTO-8 drive ok too?

(We need to update anyway, but I'd like to know the dependencies. Since
LTO-8 tapes are not currently available, we would just go with LTO-7
tapes in an LTO-8 drive and later upgrade. Otherwise we would need to
upgrade first...)

I mean the question is obvious, and I tried presales, but nobody knows.

Thanks,

Marki


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It’s about the drive.

The compatibility guide always listed drives, not cartridges.

Thing is, many times a new drive would come out, and as long as you had manufacturer drivers for your OS, NetWorker would usually be happy (since NetWorker didn’t provide its own drives). I saw LTO5 drives defined as LTO4, and it worked fine, though the %full” night look a little odd. But NetWorker writes to the end of the tape, not to a specific capacity, so it would go on its merry way.

Been a couple years since I looked, though.

Wes Ono
former NetWorker and EMC guy

> On Dec 2, 2018, at 7:19 AM, marki <jm+emcdpl@ROTH.LU> wrote:
>
> Hey,
>
> Hardware compatibility matrix indicates latest NW 8.2 compatibility is LTO-7.
>
> Does the actual tape format or the drive matter here? I.e. does it mean that it requires an LTO-7 (or less) _drive_ or is an LTO-7 _tape_ in an LTO-8 drive ok too?
>
> (We need to update anyway, but I'd like to know the dependencies. Since LTO-8 tapes are not currently available, we would just go with LTO-7 tapes in an LTO-8 drive and later upgrade. Otherwise we would need to upgrade first...)
>
> I mean the question is obvious, and I tried presales, but nobody knows.
>
> Thanks,
>
> Marki
>
>
> --
> This list is hosted as a public service at Temple University by Stan Horwitz
> If you wish to sign off this list or adjust your subscription settings, please do so via http://listserv.temple.edu/archives/emc-dataprotection-l.html
> If you have any questions regarding management of this list, please send email to owner-emc-dataprotection-l@listserv.temple.edu


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Re: NW 8.x and LTO-7: is it about the drive or the tape?
December 02, 2018 10:59PM
In regard to: [EMC-DataProtection-L] NW 8.x and LTO-7: is it about the...:

> Hardware compatibility matrix indicates latest NW 8.2 compatibility is
> LTO-7.
>
> Does the actual tape format or the drive matter here? I.e. does it mean
> that it requires an LTO-7 (or less) _drive_ or is an LTO-7 _tape_ in an
> LTO-8 drive ok too?

Well, it matters a little, but it's more about NetWorker trying to assign
a media type to each volume that's labeled. One of the primary reasons
for this is so in a mixed media environment, NetWorker doesn't try use
an incompatible drive to read from a tape volume.

As Wes said, it *doesn't* matter for NetWorker being able to fill a tape.
NetWorker will keep writing to a volume until it gets a write error, which
it treats as end-of-media.

I haven't looked at the latest evolution of LTO, but unless LTO-8 is
*drastically* different from LTO-7, you can install LTO-8 drives, make
them visible to your server or storage node, and then within NetWorker
define them as something else (LTO-7 being the obvious choice, but you
could likely use even LTO-1 and have it "work"). IIRC, NetWorker uses
whatever type you told it to set the default for block/buffer sizes for
the device, so it may very well use a different block size for e.g. LTO-1
vs. LTO-7.

Keep in mind: any tape volume that you label in a drive that you've
told NetWorker is LTO-7 will get a media type of "LTO-7" assigned to it.
That may cause some issues down the road, when you upgrade to NetWorker
9.x or 18.x or whatever, and LTO-8 is fully supported. Your first
inclination may be to delete the drives and redefine them as LTO-8, but
now you have (old) media that are 'LTO-7' (because they were labeled in
a drive that you defined as LTO-7).

I don't remember what the backward compatibility rules are for LTO drives
(write N-1, read N-2?), but assuming NetWorker has the same logic for
its LTO device handling, you'll probably be just fine.

I've done this kind of thing in the distant past, when we were going
through a library migration. I can't remember if it was when we
migrated from DLT7000 to SuperDLT or if it was between early generations of
LTO. In any case, I was forced to lie to NetWorker, telling it that
the drives were one thing (probably LTO-1) when really they were something
else (probably LTO-2).

When I could upgrade to a version of NetWorker that had a drive definition
for LTO-2, I did the following:

- redefine 3 of the drives in my library as "LTO Ultrium-2"
- leave 1 drive as "LTO-1". ** set this drive to read-only in NetWorker.
- mark all the existing volumes that had been labeled when the drives
were defined as "LTO-1" as read-only.
- label a bunch of blank tapes in the new drives, so they got a media
type of "LTO Ultrium-2" assigned to them. Again, that may have meant
they were written with a different blocksize.
- once any read-only "LTO-1" tape volumes became recyclable, *delete*
it from NetWorker, then load and re-label it in one of the "LTO
Ultrium-2" drives, so that it got the correct media type assigned to
it going forward.

Tim
--
Tim Mooney Tim.Mooney@ndsu.edu
Enterprise Computing & Infrastructure 701-231-1076 (Voice)
Room 242-J6, Quentin Burdick Building 701-231-8541 (Fax)
North Dakota State University, Fargo, ND 58105-5164


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If you wish to sign off this list or adjust your subscription settings, please do so via http://listserv.temple.edu/archives/emc-dataprotection-l.html
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Francis Swasey
Re: NW 8.x and LTO-7: is it about the drive or the tape?
December 03, 2018 05:59AM
A couple of things about LTO-8 are unique!

- The break the write n-1, read n-2 rule! They write n-1, and read n-1 only!
- If you put a NEW LTO-7 media into an LTO-8 drive, it uses it with a special format that will hold less than LTO8 media but more than LTO7 drives would write (which makes it incompatible with a real LTO-7 drive).

With those caveats (as well as what Tim and Wes told you), you should be set to make your decision.

In general, it will work and you are not likely to go out and purchase LTO7 drives to replace your LTO8 ones in the future, so you should be fine.

- Frank

> On Dec 3, 2018, at 01:29, Tim Mooney <Tim.Mooney@NDSU.EDU> wrote:
>
> In regard to: [EMC-DataProtection-L] NW 8.x and LTO-7: is it about the...:
>
>> Hardware compatibility matrix indicates latest NW 8.2 compatibility is
>> LTO-7.
>>
>> Does the actual tape format or the drive matter here? I.e. does it mean
>> that it requires an LTO-7 (or less) _drive_ or is an LTO-7 _tape_ in an
>> LTO-8 drive ok too?
>
> Well, it matters a little, but it's more about NetWorker trying to assign
> a media type to each volume that's labeled. One of the primary reasons
> for this is so in a mixed media environment, NetWorker doesn't try use
> an incompatible drive to read from a tape volume.
>
> As Wes said, it *doesn't* matter for NetWorker being able to fill a tape.
> NetWorker will keep writing to a volume until it gets a write error, which
> it treats as end-of-media.
>
> I haven't looked at the latest evolution of LTO, but unless LTO-8 is
> *drastically* different from LTO-7, you can install LTO-8 drives, make
> them visible to your server or storage node, and then within NetWorker
> define them as something else (LTO-7 being the obvious choice, but you
> could likely use even LTO-1 and have it "work"). IIRC, NetWorker uses
> whatever type you told it to set the default for block/buffer sizes for
> the device, so it may very well use a different block size for e.g. LTO-1
> vs. LTO-7.
>
> Keep in mind: any tape volume that you label in a drive that you've
> told NetWorker is LTO-7 will get a media type of "LTO-7" assigned to it.
> That may cause some issues down the road, when you upgrade to NetWorker
> 9.x or 18.x or whatever, and LTO-8 is fully supported. Your first
> inclination may be to delete the drives and redefine them as LTO-8, but
> now you have (old) media that are 'LTO-7' (because they were labeled in
> a drive that you defined as LTO-7).
>
> I don't remember what the backward compatibility rules are for LTO drives
> (write N-1, read N-2?), but assuming NetWorker has the same logic for
> its LTO device handling, you'll probably be just fine.
>
> I've done this kind of thing in the distant past, when we were going
> through a library migration. I can't remember if it was when we
> migrated from DLT7000 to SuperDLT or if it was between early generations of
> LTO. In any case, I was forced to lie to NetWorker, telling it that
> the drives were one thing (probably LTO-1) when really they were something
> else (probably LTO-2).
>
> When I could upgrade to a version of NetWorker that had a drive definition
> for LTO-2, I did the following:
>
> - redefine 3 of the drives in my library as "LTO Ultrium-2"
> - leave 1 drive as "LTO-1". ** set this drive to read-only in NetWorker.
> - mark all the existing volumes that had been labeled when the drives
> were defined as "LTO-1" as read-only.
> - label a bunch of blank tapes in the new drives, so they got a media
> type of "LTO Ultrium-2" assigned to them. Again, that may have meant
> they were written with a different blocksize.
> - once any read-only "LTO-1" tape volumes became recyclable, *delete*
> it from NetWorker, then load and re-label it in one of the "LTO
> Ultrium-2" drives, so that it got the correct media type assigned to
> it going forward.
>
> Tim
> --
> Tim Mooney Tim.Mooney@ndsu.edu
> Enterprise Computing & Infrastructure 701-231-1076 (Voice)
> Room 242-J6, Quentin Burdick Building 701-231-8541 (Fax)
> North Dakota State University, Fargo, ND 58105-5164
>
>
> --
> This list is hosted as a public service at Temple University by Stan Horwitz
> If you wish to sign off this list or adjust your subscription settings, please do so via http://listserv.temple.edu/archives/emc-dataprotection-l.html
> If you have any questions regarding management of this list, please send email to owner-emc-dataprotection-l@listserv.temple.edu


--
This list is hosted as a public service at Temple University by Stan Horwitz
If you wish to sign off this list or adjust your subscription settings, please do so via http://listserv.temple.edu/archives/emc-dataprotection-l.html
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Clark, Patti
Re: NW 8.x and LTO-7: is it about the drive or the tape?
December 03, 2018 06:59AM
One more caveat on the LTO-7 media to be used in LTO-8 drives, it is called LTO-7 type M or M8. They will not work on LTO-7 drives with encryption enabled.

Patti Clark
Sr. Linux System Administrator
Oak Ridge National Laboratory

On 12/3/18, 8:44 AM, "EMC Data Protection Q & A on behalf of Francis Swasey" <EMC-DATAPROTECTION-L@LISTSERV.TEMPLE.EDU on behalf of Francis.Swasey@UVM.EDU> wrote:

A couple of things about LTO-8 are unique!

- The break the write n-1, read n-2 rule! They write n-1, and read n-1 only!
- If you put a NEW LTO-7 media into an LTO-8 drive, it uses it with a special format that will hold less than LTO8 media but more than LTO7 drives would write (which makes it incompatible with a real LTO-7 drive).

With those caveats (as well as what Tim and Wes told you), you should be set to make your decision.

In general, it will work and you are not likely to go out and purchase LTO7 drives to replace your LTO8 ones in the future, so you should be fine.

- Frank

> On Dec 3, 2018, at 01:29, Tim Mooney <Tim.Mooney@NDSU.EDU> wrote:
>
> In regard to: [EMC-DataProtection-L] NW 8.x and LTO-7: is it about the...:
>
>> Hardware compatibility matrix indicates latest NW 8.2 compatibility is
>> LTO-7.
>>
>> Does the actual tape format or the drive matter here? I.e. does it mean
>> that it requires an LTO-7 (or less) _drive_ or is an LTO-7 _tape_ in an
>> LTO-8 drive ok too?
>
> Well, it matters a little, but it's more about NetWorker trying to assign
> a media type to each volume that's labeled. One of the primary reasons
> for this is so in a mixed media environment, NetWorker doesn't try use
> an incompatible drive to read from a tape volume.
>
> As Wes said, it *doesn't* matter for NetWorker being able to fill a tape.
> NetWorker will keep writing to a volume until it gets a write error, which
> it treats as end-of-media.
>
> I haven't looked at the latest evolution of LTO, but unless LTO-8 is
> *drastically* different from LTO-7, you can install LTO-8 drives, make
> them visible to your server or storage node, and then within NetWorker
> define them as something else (LTO-7 being the obvious choice, but you
> could likely use even LTO-1 and have it "work"). IIRC, NetWorker uses
> whatever type you told it to set the default for block/buffer sizes for
> the device, so it may very well use a different block size for e.g. LTO-1
> vs. LTO-7.
>
> Keep in mind: any tape volume that you label in a drive that you've
> told NetWorker is LTO-7 will get a media type of "LTO-7" assigned to it.
> That may cause some issues down the road, when you upgrade to NetWorker
> 9.x or 18.x or whatever, and LTO-8 is fully supported. Your first
> inclination may be to delete the drives and redefine them as LTO-8, but
> now you have (old) media that are 'LTO-7' (because they were labeled in
> a drive that you defined as LTO-7).
>
> I don't remember what the backward compatibility rules are for LTO drives
> (write N-1, read N-2?), but assuming NetWorker has the same logic for
> its LTO device handling, you'll probably be just fine.
>
> I've done this kind of thing in the distant past, when we were going
> through a library migration. I can't remember if it was when we
> migrated from DLT7000 to SuperDLT or if it was between early generations of
> LTO. In any case, I was forced to lie to NetWorker, telling it that
> the drives were one thing (probably LTO-1) when really they were something
> else (probably LTO-2).
>
> When I could upgrade to a version of NetWorker that had a drive definition
> for LTO-2, I did the following:
>
> - redefine 3 of the drives in my library as "LTO Ultrium-2"
> - leave 1 drive as "LTO-1". ** set this drive to read-only in NetWorker.
> - mark all the existing volumes that had been labeled when the drives
> were defined as "LTO-1" as read-only.
> - label a bunch of blank tapes in the new drives, so they got a media
> type of "LTO Ultrium-2" assigned to them. Again, that may have meant
> they were written with a different blocksize.
> - once any read-only "LTO-1" tape volumes became recyclable, *delete*
> it from NetWorker, then load and re-label it in one of the "LTO
> Ultrium-2" drives, so that it got the correct media type assigned to
> it going forward.
>
> Tim
> --
> Tim Mooney Tim.Mooney@ndsu.edu
> Enterprise Computing & Infrastructure 701-231-1076 (Voice)
> Room 242-J6, Quentin Burdick Building 701-231-8541 (Fax)
> North Dakota State University, Fargo, ND 58105-5164
>
>
> --
> This list is hosted as a public service at Temple University by Stan Horwitz
> If you wish to sign off this list or adjust your subscription settings, please do so via http://listserv.temple.edu/archives/emc-dataprotection-l.html
> If you have any questions regarding management of this list, please send email to owner-emc-dataprotection-l@listserv.temple.edu


--
This list is hosted as a public service at Temple University by Stan Horwitz
If you wish to sign off this list or adjust your subscription settings, please do so via http://listserv.temple.edu/archives/emc-dataprotection-l.html
If you have any questions regarding management of this list, please send email to owner-emc-dataprotection-l@listserv.temple.edu




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Re: NW 8.x and LTO-7: is it about the drive or the tape?
December 03, 2018 10:06AM
With respect to NetWorker's tape drive type definition:
If I remember it correctly, it defines 2 major parameters: block size & volume default capacity.

The rest is just standard SCSI functionality. It will apply to any tape hardware.
That's the reason why a new tape drive type which is officially not supported will almost work with any tape drive definition. Perhaps not optimally, but it will work.
I do not want to think about the number of customers who were using the wrong drive type (4mm DAT) just because it was defined as default media type.

Mixed media? - handle with extreme care. AFAIR it is still not supported in the same (logical) library.
Yes, NW can deal with it, but only if the tape has been labeled. But you can definitively load the wrong media in the wrong device.

Can you label a tape which has accidentally labeled with a lesser density with the default density? - Yes.
However, you must ensure that you load the tape into the drive and - with the first command - issue a write from BOT.
Unfortunately, every backup software runs a read from BOT instead (to verify whether a valid label exists). As a consequence, the tape drive already (the hardware already) will switch back to the density found (which also impacts the tape capacity). That's why you must run a 'basic scsi write command' with an appropriate tool/utilty. Maybe NetWorker's generate_test_tape utility can do this.
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