On B2D, does OPP set to Zero Hours mean NEVER overwrite or ALWAYS overwrite?

[Paul_Savitz]

I see various forum articles/submissions where in running Backup-to-Disk, some state to ser the Overwrite Protection Period (OPP) to "0" Hours and others are saying that you should set it to an hour if you want the media to become overwriteable as soon as possible.  I have a problem with B2D files occupying a ton of space even though they've already been backed up to tape.  How can I get the older B2D files to purge?  Apparently my answer is somewhere in OPP but not sure which setting I should go with.

Any assitance will be greatly appreciated.

[Ken_Putnam]

OPP of "0" means no protection  (though as indicated elsewhere, this can  lead to really strange results sometimes - hence the 1 hour OPP suggestion)

OPP of "Infinite - Never Overwrite" is the other extreme

does the data on your disk include GRT data?  if so, regardless of your OPP settings, that data  will not be overwritten until the disk fills up or the Disk Space Reserve has been met.  This is a design decision by Symantec, and, I think, a silly one

If/When the OPP expires, the BKF files will not be purged/deleted, their contents will be replaced.  (think of eack BKF file as a tape volume )

[Paul_Savitz]

Thanks Ken!!!

[Paul_Savitz]

One more thing...

What is the difference between:

-  Maximum Size for Backup-to-Disk files  (Backup-to-Disk Properties Page; General Tab)

and

-  Disk space reserve  (Backup-to-Disk Properties Page; Advanced Tab)

And does one affect the other?

[Ken_Putnam]

Maximum Size for Backup-to-Disk files - The max size for each BKF file.  Larger is more efficient disk space wise, but if you do all Overwrite Jobs, you can wind up with lots of unused space at the end of the last file of each backupset

Disk Space Reserve   - The amount of space to reserve for non-BackupExec data.  If you have a 500 GB drive and set the reserve to 100 GB, BackupExec will report "Disk Full"  when it reaches 400 GB.  If you dedicate a drive for B2D files as Symantec recommends, you can set the Reserve to 0

[Paul_Savitz]

I have an operations meeting shortly and need to report my findings to my team and manager.  Just to reiterate, OPP set to zero allows it to be immediately overwritten, but unexpected results could arise, thus recommended setting is the 1 hour setting to allow for media to be overwritten almost immediately.

Let me know if what I stated above is correct.

Thanks in advance.

[Ken_Putnam]

correct.

personally, I'd set media set OPP so that the tapes are protected until just before they are due to be reused and/or partition the slots so that each job goes to a separate set of tapes