What am I doing wrong?

[Steve_Rushing]

I can�t seem to get my backup scheme to work reliably.
I am trying to run 3 backup jobs each night, all using the same media set of two tapes per day. All the data will fit on these two tapes with plenty of room to spare.
We use an HP LTO tape library.

I have 5 media sets, one for each day. Each media set is two tapes.
Each day�s backup jobs use that day�s media set.

The media sets are setup for 6 day overwrite, infinite append.
The first job of the day starts at 6pm, is small (8gb) and is set to overwrite.
The second job is also small and is set to append. The big job starts at 10pm and is also set to append.

What I want to happen is for the first job to pick a tape from that day�s media set, overwrite it and then the subsequent jobs fill it up and move on to overwrite the second tape of that day�s media set when the first is full. This doesn�t seem to be happening.

This past Wed, my backup stole two tapes from another media set and wound up using 4 tapes. Some days it takes only two.

What am I missing? I�m sure if I erased the tapes ahead of time that would prevent the problem, but then it would screw up the overwrite protection period on the tapes and they would not be available for that night�s backup. I don�t want to ease them as soon as I reload them because that kind of defeats the purpose of having multiple backups!

I have been fighting this for a while and I don't know what else to do.

Thanks!
-Steve

[Steve_Rushing]

Please help!

[Steve_Rushing]

What do I need to do get some help with this?

[Ken_Putnam]

Using media sets with appropriate OPP and selecting "use overwritable media in the target media set before scratch media" should work, but seems not to in many cases

The only way to guarantee that a job will use a specific tape(s) is to set up partitions in your library, and point the jobs at the partition rather than "All Pools" or the library as a whole

See
http://seer.support.veritas.com/docs/206843.htm
http://seer.support.veritas.com/docs/262055.htm
http://seer.support.veritas.com/docs/241773.htm

[Steve_Rushing]

Thanks Ken,

I will try the partitioning.

Please help me understand how the software will handle the tape transition I described. If only the first job is set to overwrite and the subsequent jobs are all appends, what happens when it needs the second tape which may be partially filled. I want it to overwrite the second tape each time. Will that happen if only two tapes are in the partition?

Thanks again.

[Ken_Putnam]

Overwrite or Append only applies to the first tape of a BackupSet. If either type of job fills a tape up, the continuation tape will ALWAYS be overwrite

[Steve_Rushing]

That's good to hear. That's the way I understood it, but my results lately have led me to believe otherwise.

Thanks again. You have been very helpful.