I have several backup jobs that run over each weekend and two tapes are enough for all the data. However, my first job runs and backs up to tape 1, then when the second job runs, rather than appending to tape 1 (which has more than enough room), it pulls tape 2 and backs up to it. Then the next job backs up to tape 2, and the last couple jobs then go back and append to tape 1. I'm not sure why it's using the tapes in this manner, and sometimes it asks for a third tape when tape 2 is full and tape 1 is far from empty.
Also, if I have a job that is say 200GB total, and my tape has only 150GB of space left, but with compression the 200GB job always backs up to less than than 100GB, will BE still refuse to run the backup to the tape since theoretically it only has 150GB free on the tape?