Media Management starting new tape instead of appending by Backup Exec 11d

Check the policy. I thi k it requireds a new tape in that situation.

I don't have a policy associated with that backup (column is blanked in the panel "Job Configuration" (i guess my version isn't english localized). Is there something to do to associate a special policy to this job so as to keep on appending even after a 2 tapes last backup ?

I just looked into the 2 default policies available and tries to create another one but didn't find anything useful to force the tape behaviour i want.

I appreciate your help but i think my point isn't very clear ; my problem is not about the choice of the 2nd tape when current backup need to span to another tape, that's allright.

The problem is the next day after a "spanned" backup ... when next backup chooses another tape to start its job when the 2nd tape of yesterday would be allright to append to.

Example :
Day 1 : backup on LTO23
Day 2 : backup on LTO23
Day 3 : backup on LTO23 + LTO36 <= just a bit of data on LTO36 (plenty of space left)
Day 4 : backup on LTO12 <= that's my problem i want this backup to be appended on LTO36

I would like
Day 1 : backup on LTO23
Day 2 : backup on LTO23
Day 3 : backup on LTO23 + LTO36
Day 4 : backup on LTO36

If you say there is no way i can change this behaviour (or maybe the problem is with the tape library robot ?)
i will consider this question closed. Thanks for your answers.

Apologies. I misread the question.
What you want should be working. I assume your job is set to "append to media, overwrite if no appendable media is available"? I assume it is, because otherwise in your example, day 2 would not be writing to media LTO23.
I can see no real explanation as to why you get the behaviour you describe. It certainly is not the normal behaviour I would expect. Maybe you could try one thing though - what if you change your job to "append to media - terminate job if no appendable media is available". Does the job on Day 4 append to LTO36 with that setting?

One other thing to check - just make sure that media LTO36 in your first example is not "Export Pending" as described in http://www.symantec.com/docs/TECH60241. I would be very surprised it is, but just check for completeness.

Yes, the job is set to "append to media, overwrite if no appendable media is available". When i refill the autoloader, i only put tapes part of the media set associated with this job and recyclable. I inventory all of the new tapes and they are all blue (overwritable). Then the scheme i described sets in.

Between christmas and new year's day, different jobs are planned and next set of complete/differential backups starts early january. I will test your advised setting and check for "export pending".

Give me 2 weeks and i 'll report then. Thanks for your time

After some more backups and change of settings (no "export pending" noticed and "append to media - terminate job if no appendable media is available"), i have still the same tape rotation pattern occuring. Any other ideas ?

With the job set to "append to media - terminate job if no appendable media is available" are none of the jobs failing?
Are all the tapes used in that tape rotation pattern part of the same media set?

I really can't see why this would be happening.

I had jobs failing normally i guess if no space is left on any tape and if it's "impossible to append" to any tape. Other than that jobs kept on executing normally with the same behaviour after a job spanned upon 2 tapes. I specifically imported into the tape library only media from the same media set to avoid one more cause of problem.
I'll revert from now on to "append to media - overwrite if no appendable media is available" since it hasn't solved the problem.

You wouldn't have partitions set up in Backup Exec, would you? Send a screenshot of the Devices tab, with the devices all expanded.
How many different jobs do you have for this rotation? Is it just the one job?

I don't know what a partition is in BE. Concerning the job, It's a differential backup.
Concerning the snapshot, it went this week like this :
monday : LTO111
tuesday : LTO111
wednesday : LTO111 + LTO101
thursday : LTO133
friday : LTO133

I still have LTO101 as an "orphan" tape :-(

If you ask, both tapes labelled "DIG" concerns another job which occured last week-end

Thanks for your help (again!)

OK, tonight's backup should fill up LTO133 and now LTO101 is removed. There is a screen capture of the library before the backup with a focus on LTO133. I don't remember the appendable status of LTO133 from last week, sorry but your words make me think i didn't have that behaviour when i fed in blank (out of the box) tapes, way back then. Now i'm recycling only already used tapes (all are overwritable but some are full (impoosible to append) and some are not (appendable because they typically are previous orphaned tapes from past spanned backups)).

 
I'll report tomorrow after the backup anyway.

To answer your question, after checking, LTO133 was last used as a 2nd tape in a spanned backup 8 months ago. So i guess its status was appendable because there was plenty of space left on it.

Tha backup filled up LTO133 then chose LTO051

I will close this question now. Thanks for all your help - what i considered weird behaviour was normal in the end, i did not distinguish between appendable and overwritable media i put into the tape library. Thanks again Honmapog for your time and all the explanations.