Reuse offsite tape in NetBackup Vault

[liuyang]

Hi, I have one master server and one media server (both are NBU 7.0.1 on Windows 2008 R2). My tape library is IBM TS3310 with 6 x LTO5 tape drives. I have configured Vault for offsite tape store. The users' requirements are:

Retention is 2 weeks for offsite tape.

Two tape media for each type of server, e.g., there are two tape medias for web server for offsite store. Tape 1 for week 1 and tape 2 for week 2. For week 3, tape 1 will be reused since the backup images on tape 1 are expired. 

Is it possible to meet the requirements above in Vault? I found one issue is offsite pool may get a new tape media from scratch pool instead of reuse the previous tape.

Thanks in advance.

[RiaanBadenhorst]

Hi,

This type of configuration is always complicted in NetBackup. The MM component of NBU does media management for you and its not always efficient to configure backups in this way, i.e. One media for the webserver, one media for the mail server, one media for the database server, etc. In most (not all) cases you're wasting space on the media if you run this type of configuration because the first tape will have 300Gb, the second maybe 500, and so forth and so forth. In the end you might have used 5 media's but the total space required might equal 2 tapes. This is also influenced by your number of drives but you'll understand what I'm getting at.

For efficient media utlilization always try to have as few pools and retentions as possible.

If you want your scenario to work you should probably not use a scratch pool, then you can control which media goes into which pool. But that really defeats the purpose of paying top dollars for a product like NetBackup that is supposed to take care of all these functions.

You might also run into situations where at backup start time, the media has not expired. Even though its set to expire in one week, the times might be slightly off i.e backup starts at 20:00, expiry is set to 20:11. And then you'll find that tapes get taken from the scratch pool.

Have a look what the other forum users say, but thats my opinion.

[liuyang]

Hi Riaan, thanks for your replies. The requirements are from the management so I may not be able to convince them to change. Previously we use another software and that software is able to do tape clone.

In NBU, in that case, can I use three tape media instead of two for each type of server? The retention is still 2 weeks. So there will be always a tape media in which the backup images are expired. The duplication of backup images will be written to that tape media then. Is it OK to do that?

[RiaanBadenhorst]

Hi,

Yes, its possible if you want to do it like that. Like I said, if you're going to use scratch the media id's might move around between the pools as and when netbackup selects them. It chooses them randomly.

[liuyang]

Hi Riaan, thanks. I have another question: if all the duplicated backup images on a tape media expire, will the tape be automatically moved to scratch pool? When I inject such a tape to the tape library, will this tape go to the respective vault volume pool or go to scratch pool?

[Will_Restore]

When the images on a volume expire, NetBackup returns it to the Scratch volume pool if it was allocated from the Scratch pool.

New media will go to the default Netbackup pool unless you specify otherwise on inject, or set up a barcode rule to automatically move new volumes to the Scratch pool.

[liuyang]

Thanks. I have another question: is there a way to manually expire Vaulted tape media? In Vault, I duplicated some backup images to the tape in offsite volume pool and then ejected the tape. When I insert the tape back to the library, the tape returns to the offsite volume pool and it shows it will expire in two weeks' time. If I want to reuse the tape/overwrite the tape for the next Vault session immediately, how should I do that? I try to expire the duplicated images on the tape but was unable to find a way to do that.

[RiaanBadenhorst]

you can expire all the images on a specific media with

bpexpdate -m "mediaid" -d 0 -force

Please use this command carefully as it involves the destruction of backup images. Rather ensure your retentions are setup correctly, then you don't need to use it.