BE 12.5 sometimes needs second tape, sometimes not
I back up a couple of servers using BE 12.5 onto an HP LTO3 drive
I have just one job defined that runs in the night Monday to Friday.
Recently the job has started to require a second tape to complete the backup, almost always on Wednesday and Thursday. The job run fine on the other weekdays and doesn't require a second tape. This week on Monday the job backed up 410GB on one tape but on Wednedsay it was asking for a new tape after only 215GB and finally finished the job on two tapes with a total of only 310GB.
What I don't understand is that it's just one job repeating every 24 hours so the setup is always the same. I've even erased the tapes and used new tapes for the Wednesday and Thursday backups but I the job always wants a second tape on these days, even though it never gets near the native capacity of the tapes.
Anyone got any ideas what might be causing this strange behavior?
Thanks in advance