We've been using TSM for VE for about a year now and while it's been great for onsite restores, our recent DR test was troubling. We've been using the IFINCR strategy and while I was expecting restores from tape to be slow, I wasn't expecting restores to drag into the 5-6 hour range for a small VM (40 GB.) I know that the admin guide recommends periodic-full for VM tape retention, but we use dedup disk onsite and we're already experiencing pressure on our daily backup intake volumes and disk usage, so I'd prefer not to have to change our backup strategy due to the increase caused by periodic-full in both daily traffic and storage.
Is there any other way I could conceivably improve restore times from a tape copypool while still using IFINCR as my backup method? Here are a few things I considered: 1) A separate collocated copypool for the VECTL data. This would live on one tape easily and would reduce the number of mounts required for a restore. However, if that tape goes bad, I'm totally screwed in a DR situation because there's no way to restore VM backups without the control files. I'm assuming that if I use collocation by node, TSM will generate a new tape every day with all the CTL files and call back the old one. Am I right in that assumption? 2) Could I do an IFFULL backup every few weeks or even every month to limit tape mounts? 3) ??? If anyone with some practical experience in using TSM for VE with tape copypools could offer some guidance, I'd appreciate it. Thanks, Matthew McGeary Technical Specialist PotashCorp - Saskatoon 306.933.8921
