Richard, I'll try to get you some detailed information from our Cyrus support person. We have been running Cyrus for years. A couple of years ago we had some filesystem corruption and had to restore a mail spool filesystem from TSM. It took much longer than we wanted/expected it to. Yes, it's just the "restoring large quantities of small files" problem.
We have upgraded our TSM DB disks to FAStT 900, 15K rpm, and that has helped some. Parallel restore sessions helps some. Using 'testflag disable nqr' helps some. Other things we have thought about, but have not yet implemented, include: - using vTape or serial access disk volumes, for keeping the email backups. Most of the performance penalty is involved in tape skipping. When restoring dis-contiguous files off of tape, it takes time to reposition the tape. This adds up. This penalty is avoided with vTape. - using a combination of image backup and filesystem backup. Restoring an image first, then applying incremental file-based backups should be faster than just restoring everything at the file level. Of course, if your corruption is backed up with the image, you can still resort to the file-level backups. The image doesn't have to be in TSM, but could also be storage-system based (i.e., flash copy). ..Paul At 09:32 AM 5/16/2006, Richard Sims wrote:
We're a site who has been using IMAP with mbox style mail "folders" for a decade. It's obvious that as we boost mail quotas, mbox "does not scale". Thus, we are planning for a conversion to Cyrus, on Linux. For planning purposes, I'd like to get input from Cyrus sites as to issues they've encountered in performing backups and restorals, particularly with coherency, given that each message becomes an individual file. The Many Small Files issue is apparent, but there are probably other things that sites have learned the hard way that could help others. One unobvious issue I can think of is how to best perform mail investigations via restorals, as called upon in subpoenas. (A search of the ADSM-L archives turns up next to nothing on Cyrus and TSM.) I'd be happy to hear any other practical recommendations for efficiently implementing Cyrus, based upon site experiences (disk arrangement, file system type, directory architecture, etc.). Whereas that would be off the TSM topic per se, feel free to email me directly ([EMAIL PROTECTED]). thanks, Richard Sims
-- Paul Zarnowski Ph: 607-255-4757 Manager, Storage Systems Fx: 607-255-8521 719 Rhodes Hall, Ithaca, NY 14853-3801 Em: [EMAIL PROTECTED]
