Backup Central

Hi,

Let's say I have a recovery that will require 7 volumes and that some of
these volumes are still appendable. If I start the recovery, and I know
it won't complete before the nightly backups start, and I don't want to
postpone the backups, is there anything that can be done to ensure that
the recovery will not be hampered?

For example, I was thinking that maybe just before it requests the next
tape, the backups might try to sneak in and use that tape to write data
and thus delay the recover, forcing it into limbo, so I write-protected
all the affected tapes to prevent this. I guess I SHOULD have also
changed one of the drives to read-only and loaded the first required
tape so NetWorker would use that device for the recovery, and the drive
would not get used for writes, and then the recovery should not be
affected by the backups.

Does this sound like the best strategy, and is any of this necessary?
Who has the right of way here? I want to say that there's nothing to
prevent a backup from sneaking in and grabbing the drive or one of the
tapes in between a tape change operation if you don't take these
measures to guard against it? Maybe the recovery will reserve the drive
it starts with for the duration of the recovery? Could have sworn I've
seen that theory debunked before unless device was set to read-only.

George

Note: To sign off this list, send a "signoff networker" command via email
to listserv < at > listserv.temple.edu or visit the list's Web site at
http://listserv.temple.edu/archives/networker.html where you can
should be sent to stan < at > temple.edu

George Sinclair wrote:
Hi,

Let's say I have a recovery that will require 7 volumes and that some of
these volumes are still appendable. If I start the recovery, and I know
it won't complete before the nightly backups start, and I don't want to
postpone the backups, is there anything that can be done to ensure that
the recovery will not be hampered?

For example, I was thinking that maybe just before it requests the next
tape, the backups might try to sneak in and use that tape to write data
and thus delay the recover, forcing it into limbo, so I write-protected
all the affected tapes to prevent this. I guess I SHOULD have also
changed one of the drives to read-only and loaded the first required
tape so NetWorker would use that device for the recovery, and the drive
would not get used for writes, and then the recovery should not be
affected by the backups.

Does this sound like the best strategy, and is any of this necessary?
Who has the right of way here? I want to say that there's nothing to
prevent a backup from sneaking in and grabbing the drive or one of the
tapes in between a tape change operation if you don't take these
measures to guard against it? Maybe the recovery will reserve the drive
it starts with for the duration of the recovery? Could have sworn I've
seen that theory debunked before unless device was set to read-only.


I'd say this is entirely the right strategy and it is what I would do in
those circumstances.

Note: To sign off this list, send a "signoff networker" command via email
to listserv < at > listserv.temple.edu or visit the list's Web site at
http://listserv.temple.edu/archives/networker.html where you can
should be sent to stan < at > temple.edu

Rather than using the write protect device on the tape we tend to mark the
volume as read only in the GUI - might be I'm too lazy to walk to the
jukebox.

Note: To sign off this list, send a "signoff networker" command via email
to listserv < at > listserv.temple.edu or visit the list's Web site at
http://listserv.temple.edu/archives/networker.html where you can
should be sent to stan < at > temple.edu

On Thu, 10 Mar 2005, Howard Martin wrote:

Rather than using the write protect device on the tape we tend to mark the
volume as read only in the GUI - might be I'm too lazy to walk to the
jukebox.

Even if you set the write-protect tab on a tape cartridge, NetWorker may
still attempt to write to that tape if it is still appendable. I see no
advantage to setting the write-protect tab on cartridges that NetWorker
uses unless maybe you ship the tapes off-site for safe keeping. Setting
the tape volume as read only from within NetWorker seems adequate to me.

Note: To sign off this list, send a "signoff networker" command via email
to listserv < at > listserv.temple.edu or visit the list's Web site at
http://listserv.temple.edu/archives/networker.html where you can
should be sent to stan < at > temple.edu

Networker operations are priority based in general.
There are 3 general major operations Networker does.
1. Recover
2. Backup
3. Clone
The higher in the list above the higher the priority.
This said the question remains when will a higher priority operation
suspend a lower priority one.
This lower priority task suspension will only take place at "volume
switch" time (unload/end of use).
Assuming all your drives are busy backing up and you want to do a
recover, the recover will wait until the first unmount could be done to
a currently mounted volume. At this time the recover will request the
first needed tape to be mounted in the just freed device.
As recovery has the highest priority, this device used will not be given
up to any lower priority operation as long as the recover has not
finished.
Once the recover has finished the suspended operation will continue.
Itzik

-----Original Message-----
From: Legato NetWorker discussion
[mailto:NETWORKER < at > LISTSERV.TEMPLE.EDU] On Behalf Of Stan Horwitz
Sent: Thursday, March 10, 2005 16:09
To: NETWORKER < at > LISTSERV.TEMPLE.EDU
Subject: Re: [Networker] Right of way for recovers?

On Thu, 10 Mar 2005, Howard Martin wrote:

Rather than using the write protect device on the tape we
tend to mark
the volume as read only in the GUI - might be I'm too lazy
to walk to
the jukebox.

Even if you set the write-protect tab on a tape cartridge,
NetWorker may still attempt to write to that tape if it is
still appendable. I see no advantage to setting the
write-protect tab on cartridges that NetWorker uses unless
maybe you ship the tapes off-site for safe keeping. Setting
the tape volume as read only from within NetWorker seems
adequate to me.

--
Note: To sign off this list, send a "signoff networker"
command via email to listserv < at > listserv.temple.edu or visit
the list's Web site at
http://listserv.temple.edu/archives/networker.html where you
regarding this list should be sent to stan < at > temple.edu


Note: To sign off this list, send a "signoff networker" command via email
to listserv < at > listserv.temple.edu or visit the list's Web site at
http://listserv.temple.edu/archives/networker.html where you can
should be sent to stan < at > temple.edu

I see no
advantage to setting the write-protect tab on cartridges that NetWorker
uses

You're right, as long as the tape isn't recyclable. The write protect tab
prevents NetWorker from relabeling an expired tape; setting it to readonly
doesn't. I would recommend doing both for normal restores, just in case
someone forgets to remove the tape from the jukebox.

Conrad Macina
Pfizer, Inc.


On Thu, 10 Mar 2005 09:08:45 -0500, Stan Horwitz <stan < at > TEMPLE.EDU> wrote:

On Thu, 10 Mar 2005, Howard Martin wrote:

Rather than using the write protect device on the tape we tend to mark the
volume as read only in the GUI - might be I'm too lazy to walk to the
jukebox.

Even if you set the write-protect tab on a tape cartridge, NetWorker may
still attempt to write to that tape if it is still appendable. I see no
advantage to setting the write-protect tab on cartridges that NetWorker
uses unless maybe you ship the tapes off-site for safe keeping. Setting
the tape volume as read only from within NetWorker seems adequate to me.

--
Note: To sign off this list, send a "signoff networker" command via email
to listserv < at > listserv.temple.edu or visit the list's Web site at
http://listserv.temple.edu/archives/networker.html where you can
should be sent to stan < at > temple.edu

Note: To sign off this list, send a "signoff networker" command via email
to listserv < at > listserv.temple.edu or visit the list's Web site at
http://listserv.temple.edu/archives/networker.html where you can
should be sent to stan < at > temple.edu

On Fri, 11 Mar 2005, Conrad Macina wrote:

I see no
advantage to setting the write-protect tab on cartridges that NetWorker
uses

You're right, as long as the tape isn't recyclable. The write protect tab
prevents NetWorker from relabeling an expired tape; setting it to readonly
doesn't. I would recommend doing both for normal restores, just in case
someone forgets to remove the tape from the jukebox.

Activiating the write protect tab would cause SCSI errors, at least on the
equipment I have. Wouldn't changing recyclable tapes to be manually
recyclable via the GUI protect the data on those tapes without causing NSR
to needlessly mount them and than generate SCSI errors and still allow
their contents to be scanned in? Depending on your jukebox's device
settings, what you propose might also cause a tape drive to become
disabled if you have a very low error count setting.

Note: To sign off this list, send a "signoff networker" command via email
to listserv < at > listserv.temple.edu or visit the list's Web site at
http://listserv.temple.edu/archives/networker.html where you can
should be sent to stan < at > temple.edu