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Disk staging doesn't move images from in-flight backups?

altmiket
Level 4

I have a NBU 6.5.5 setup on Solaris 10, with a disk storage unit set up to stage backups to tape.

It appears as if NBU is duplicating images to tape properly, but only for backups that are totally complete - I.E. it will not stage images to tape for a backup that is running.

This means that my disk storage unit must be equal to or larger than the largest backup I can run.  E.G. if i have a 8TB DSSU, I can only run a backup that is a max of 8TB in size.

 

I was under the impression that disk staging would duplicate the images regardless of the status of the backup (except for backups that have outright failed).  That is, I need to be able to run backups that are larger than my DSSU.

 

is there any way to make that work?

 

Also I have read that NBU is supposed to pause backups if the DSSU is nearly or completely full, to allow it time to dupe images to tape and expire them, but that doesn't appear to be working.  I have run into several error 129 DSSU is full problems, which just tank the backup, and do not allow it to be resumed, they must be restarted completely.   Any ideas there?

 

Thanks as always.

1 ACCEPTED SOLUTION

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Marianne
Moderator
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Disk staging will only duplicate completed backups.You configure a disk staging shedule to duplicate completed backups.

Have a look at this section in NBU 6.5 Admin Guide I for UNIX/Linux http://www.symantec.com/docs/TECH52801 :

Disk staging storage unit size and capacity considerations
To take advantage of basic disk staging requires that the NetBackup
administrator understand the life expectancy of the image on the Stage I storage
unit.
......
The minimum disk size is the smallest size that is required for the successful operation of the disk staging logic. The minimum size must be greater than or equal to the largest combined size of
the backups that are placed on the storage unit between runs of the disk staging
schedule.

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3 REPLIES 3

Marianne
Moderator
Moderator
Partner    VIP    Accredited Certified

Disk staging will only duplicate completed backups.You configure a disk staging shedule to duplicate completed backups.

Have a look at this section in NBU 6.5 Admin Guide I for UNIX/Linux http://www.symantec.com/docs/TECH52801 :

Disk staging storage unit size and capacity considerations
To take advantage of basic disk staging requires that the NetBackup
administrator understand the life expectancy of the image on the Stage I storage
unit.
......
The minimum disk size is the smallest size that is required for the successful operation of the disk staging logic. The minimum size must be greater than or equal to the largest combined size of
the backups that are placed on the storage unit between runs of the disk staging
schedule.

altmiket
Level 4

Hmm.  So even if I have disk staging runs happening throughout the duration of a very large backup to DSSU, it won't duplicate any of the images for that backup, until the backup is 100% complete.

 

That doesn't really jive with the sizing logic as mentioned in the admin guide - the docs (as I read them) imply that it will start duplicating images to tape, as soon as the staging job kicks in.

 

But that wouldn't be the first time NBU didn't function as I expected.

 

Thanks for the info Marianne.

Marianne
Moderator
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There are tons of reasons outside of NBU control that could cause backups or duplications to fail.

Starting duplication before confirmation of successful backup or cleanup before successful duplication would be calling uncle Murphy!

The whole idea with disk backups is to have them available for quick restores. At least until next backup cycle. Best to plan and provide disk space for 2 full backups. Otherwise you might as well write directly to tape.