Simon> I am just quoting my learned college in Mentor, who was advised Simon> by Rational that incremental backups were not the way to go.
I can understand their rational (sorry for the pun), since making full backups each time reduces the chances of any data loss, but the time to do so each night is prohibitive. Though these days, using either VxFS filesystem snapshots, or storing the VOBs on toasters and using snapshots there, you can do the backups outside of normal hours, or even export the data to another host and dothe backups there. It depends on your money mostly. :]
Simon> I see your point that there's little you can do with a volume Simon> of your size, but since we are talking about a database with Simon> file history, should you suffer any mishap in your backup Simon> software, would that cause a major problem in your ability to Simon> restore?
Sure, but since Legato (and NetBackup as I understand it, still not intimately familiar with it) dumps the file indexes with each backup, in the worst case I can just scan the backups to do a restore.
And when you're doing a restore of a VOB, you're restoring *all* the data, just not specific files, since you need to restore them all to the same known state to guarenttee that you get a good VOB db back.
Simon> We use netbackup, and I know there are times when the software Simon> misses a backup. It did last night!
Now if you were using a toaster for backup storage, you'd be backing up the snapshot, and of course you'd keep a couple of days of snapshots around for just such an occurance?
The nice thing about VOB backups, is that after a while you're not going to go back and restore them, since the data is cummulative (ideally, I'm ignoring if you purposefully nuke data in your VOBs). So once a week or two have gone by, you really don't need the backups, since the data is there.
John John Stoffel - Senior Unix Systems Administrator - Lucent Technologies stoffel@lucent.com - http://www.lucent.com - 978-399-0479