Used capacity of tape

[Rachel_Chipman]

In Backup Exec, the tapes used for a FULL backup indicate that about 400 MB of the tape capacity is being used.  I do not actually believe this is the case, however, why would Backup Exec show this?

Also, since our Full backups use more than 1 tape, the overwrite protection of the first 4-5 tapes are set to Infinite - Don't Allow Overwrite instead of the number of days set in the Media Set.  Any suggestions as to why this is?

Thank you.

[Ken_Putnam]

1)  What kind of tapes are they?  How much data do you think is being written?  Are you using HW or SW compression?

2)  This question comes up from time to time, and has never been officially addressed by Veritas/Symantec

My guess is that this is so that BackupExec manages the OPP/APP by the last tape in the set, regardless of how many tapes are in the backup set.  That is none of the previous tapes are available until the last tape has expired

It is possible for the first tape in a set to close the day before the last (or in extreme cases maybe two days ) and as such if you overwrote it, the integrity of the backup set would be compromised before the OPP of the set as a whole has expired

Message Edited by Ken Putnam on 09-18-2007 10:12 AM

[Rachel_Chipman]

The tapes are DLT IV tapes 40/80 capacity.  Hardware compression is enabled and if this isn't available, the jobs are set to use software compression. 

I believe the full amount of data that can fit onto a tape (37 GB) is being written to the tapes.  The reason I say this is because total backup size to backup is 200+ GB of data and the amount of tapes being used represents this amount per tape.