We have a Dell Equallogic PS4000 we are using for a SAN. We have a VM running Server 2008 on the EqualLogic. The E: drive of the VM is an iSCSI connected volume on the Equallogic. On that drive /volume I have a little over 1TB of data that is used for our office CMS program.
The EQL is setup to take 4 snapshots over 24 hours, one snapshot a week, and one snapshot a month. The reserve is 85% of the volume size.
We backup this EQL volume - the E: drive in Server 2008 over the LAN (not SAN) to a Server 2003 box with an attached SAS LTO-4 tape drive.
When I started working here, full tape backups were running overnight of this shared network drive. The window for the backups took the entire night. Well, the backups were getting dangerously close to production hours so I moved us to a differential backup plan. Now we take differential backups M-Th with a full backup on Friday.
Ever since we have instituted the differential backups, my weekly and monthly EQL snapshots have grown so large that they get wiped out to save space. I suspect it has something to do with the archive bit being reset on the files in the tape backups.
Does anyone have any advice on how to move forward? We use an older copy of CA Arcserve (12.5) and I do not believe that there is a differential option that does not use the archive bit.
I would preferably like to maintain both our tape backups and a month's worth of EQL snapshots if at all possible without increasing my current EQL disk usage.