>>Question: does anyone have "practical" experience with subfile backups?
Yep - about 350 Win2K machines using it for last 2 years. Our server is still 4.2.1.15, clients at 4.2.0.0; haven't tried it yet at 5.1 server. >>Is it easy to implement? Yep. Really straightforward. Easy to test, easy to implement. Don't forget you have to SET SUBFILE ON at the server end. We use subfile for all files on the machine. But, you can restrict it to certain files using include/exclude.subfile options. We started out using it to attack the problem of large .pst files on many machines. Cut our overall nightly load by about 30%, probably extended the life of my server by a year. >>Is there anything to pay special attention too? * it works by creating a /cache directory under the /baclient directory; MAKE SURE you exclude that from backups! * DON"T FORGET that subfile DOESN"T HELP YOU on restores! Make sure you manage your user expectiations in that area. * If you aren't using collocation on the server end, better think twice - for every restore, you have to restore the base and the last delta file. Will lead to extra tape mounts without collocation. We found it didn't cause any noticeable increase in restore times, but we use collocation and very fast tape. * you probably saw that it doesn't apply to files over 2 GB, just be aware of that. * we also had occasional problems where a machine would stop backing up because the subfile cache (on the client end) would get corrupted. But the easy fix was just to delete the entire cache directory and let it build a new one on the next backup; happened so infrequently we never tried to pursue a fix with IBM. * the stats in dsmsched.log show the size of the ORIGINAL file, not the size of the subfile that actually got backed up. * Only the backup-complete stats will ever give you an idea of how much data actually got sent. I whacked it around, rebooted in the middle of a backup, deleted the cache, did everything I could think of to break it. NEVER could cause errors on restores. There were problems in 4.1 and 4.2 servers where the subfiles didn't expire completely when they should, but never any data integrity problems. We do a lot of full restores, right down to the user profile and the last icon, and never had a problem. You'll like it!
