First, you aren't really doing what you think you're doing: providing the ability to restore data back to any point in the previous 90 days. You get seven days for a file that changes every day.
Steve is right: should probably do something like verexists=unlimited and retextra=21. That way if you do a backup more than once a day you can still get 21 days worth of restores. This boils down to how many files really change 21 times in 21 days. Most files won't do that. Large things, like SQL and Exchange databases will. But you wouldn't really want to restore your SQL database back 21 days in any event. How would you get back to scratch? You couldn't. So keeping these types of things for shorter periods makes more sense. Anecdotally, my experience has been that increasing/reducing the numbers does not generally result in a ton more storage consumed/saved as most files are created and then never changed (or deleted). They get backed up the one time and then live until they are deleted and retonly is reached. I would definitely get to the 21/21 soon, though, as your user's expectations are probably different from what you're providing! Kelly Lipp CTO STORServer, Inc. 485-B Elkton Drive Colorado Springs, CO 80907 719-266-8777 x7105 www.storserver.com -----Original Message----- From: ADSM: Dist Stor Manager [mailto:ads...@vm.marist.edu] On Behalf Of Steven Harris Sent: Wednesday, March 18, 2009 3:24 PM To: ADSM-L@VM.MARIST.EDU Subject: Re: [ADSM-L] Calculating Change in Backup Environment Dennis, FWIW, I don't like a N days/N versions strategy. It can have unexpected side effects. N Days/unlimited versions has more predictable behaviour and also is more efficient at expiry time. Regards Steve. Steven Harris TSM Admin, Sydney Australia "Dennis, Melburn (IT Solutions US)" To <melburn.den...@s ADSM-L@VM.MARIST.EDU IEMENS.COM> cc Sent by: "ADSM: Dist Stor Subject Manager" [ADSM-L] Calculating Change in <ads...@vm.marist Backup Environment .EDU> 18/03/2009 11:46 PM Please respond to "ADSM: Dist Stor Manager" <ads...@vm.marist .EDU> Currently, our backup environment employs a 90-day / 7 revision backup policy. My customer has come to me to find out how much our backup data would grow or shrink if we went to a 21-day / 21-revision backup policy. Have any of you out there experience requests like this before, and if so, how were you able to get a reasonable guestimate of this. Mel Dennis Systems Engineer II Siemens IT Solutions and Services, Inc. Energy Data Center Operations 4400 Alafaya Trail MC Q1-108 Orlando, FL 32826 Tel.: 407-736-2360 Mob: 321-356-9366 Fax: 407-243-0260 mailto:melburn.den...@siemens.com www.usa.siemens.com/it-solutions
