Hi Mark, Thanks for your comments. I've decided to not go with subfile backups because (from training late last year) I understood that a 1MB file could be backed up over many volumes, thus being insanely slow to restore.
The spike of 120GB isn't a huge problem. Currently, we're only have about 2TB of data that needs backing up. We've installed a IBM TS3200 (44 slots) with 2x LTO3 drives. Along with a 500GB disk pool that clients spools to first. At 3 backup revisions of most of the data, we should have room for expansion. However, on thinking about that 500GB, I'll probably up it as one of our servers is expected to grow beyond that in size. Thanks again for the comments. Cheers, Jason -----Original Message----- From: ADSM: Dist Stor Manager [mailto:ads...@vm.marist.edu] On Behalf Of Mark Stapleton Sent: Wednesday, 21 January 2009 10:51 AM To: ADSM-L@VM.MARIST.EDU Subject: Re: [ADSM-L] Unexpected behavior - Win2k3, TSM 5.4, NTFS permissions From: ADSM: Dist Stor Manager [mailto:ads...@vm.marist.edu] On Behalf Of Jason Clarke Last night, the client backed up 129GB, which is about 125GB more than normal. On any given day, during the holidays, theres about 2-3GB of changed files. However, I did change a permission on a directory/folder tree that contains 125GB of files. I'm guessing TSM has backed up the whole file because of the permission change. I'm guessing this is because subfile backup isn't being used here. If subfile was turned on for that client, would it reduce the amount of data it decided to backup? Yes, subfile backups would decrease the amount of data you would have backed up. However, you will eventually have to back up the entire set of files eventually, because subfile backups allow a limited number of deltas to be backed up, and will only affect files greater than 10kB and less than 2gB. Also keep in mind that if you have, say, 100,000 files, and you have 5 deltas for each file, you're going to have to make restore 600,000 locations on tape--1 for the last full backup of a given file, and 5 for its subsequent deltas. Subfile restores are very, very slow, and are more designed to accommodate backups across slow (i.e., T-1) bandwidth pipes. TSM treats files as whole entities. When you change permissions on a file, TSM will back it up again. Might I suggest that you stage such mass changes so that you don't get hit with such a spike again? -- Mark Stapleton System engineer, CDW No virus found in this outgoing message. Checked by AVG. Version: 7.5.552 / Virus Database: 270.10.10/1903 - Release Date: 1/19/2009 8:52 PM
