Understanding Tape and GFS

[rocketcoder]

Hi all,

My company recently got a tape drive. The purpose for getting the tape drive is to free up space in our repositories by offloading the GFS copies to the tapes. I'm trying to understand how this is done. From my understanding, a GFS Tape backup job just copies the GFS backups, but doesn't delete them from disk. Would I just adjust the backup job to only retain 1 weekly and then setup the GFS Media Pool to append the weekly? What would I do when the tape is full and the data on the tape is no longer relevant? Or is there another way to properly do this? The data in GFS backups is likely never to be needed, but needs to kept in case of a disaster.

[david.domask]

Hi Evan, welcome to the forums.

>From my understanding, a GFS Tape backup job just copies the GFS backups

Not quite -- Tape GFS creates archival GFS points (full backups) based off the current restore point in the source backup chain. It checks the most recent restore point that matches the current GFS period it's trying to backup; if the most recent restore point is a full backup (vbk) , the backup is copied to tape, and if it's an incremental (vib), a Virtual Full backup is created.

For example, assume you had a Tape GFS job with weekly GFS configured; today is a Weekly GFS day. The source job's most recent restore point is an incremental backup. The tape GFS job will find this incremental backup (vib), produce a Virtual Full directly on tape from this incremental backup, and place it in the Weekly media set.

So you don't need to do anything to the source job, the tape backup doesn't have any influence on the source backup files it is reading from.

>What would I do when the tape is full and the data on the tape is no longer relevant?

This is handled by the Tape Retention - after a tape is full or the media set closes, it will be marked as "expired" when the tape protection period is completed, then the tape will be eligible for overwrite.

Give our Tape FAQ a read as it helps to introduce a few concepts with Tape that may help with your planning.

Thanks!

[rocketcoder]

Hi David,

Thanks for the information. It sounds like the tape job still doesn't remove the GFS backup from the disk repository though. Is there a way to offload the GFS backups to tape and remove the from the disk?

[david.domask]

You're very welcome for the information.

And you are correct, the Backup to Tape jobs (GFS or Simple Media Pool) do not have any influence on the source data they are backing up to tape, they create copies of the backups on tape. Use retention on the source job to ensure that the backups are being cleared out periodically when no longer required.

[Safamahvash]

great information

[rocketcoder]

Hi David,

That leads me back to my original question. How would I adjust the retention policy? Would I just adjust the backup job to only retain 1 weekly and then setup the GFS Media Pool to append the weekly?

[david.domask]

Hi Evan,

Yes, to control the removal of backups on disk, adjust the source job retention.

As for the tape job, I may be reading your sentence too literally when you say "append"; the tape retention is separate from the disk retention, so you can set within the GFS Media Pool the desired protection period. So for example if you want to keep the backups on tape for 2 weeks, set the GFS Media Pool weekly settings to 2 weeks. The source backup copy's retention will handle the on-disk backups, and the tape protection period will handle protecting the tapes and marking them as eligible for overwrite once the protection period is complete.