We're in the middle of doing something similar. We have 17TB of windows file/print data being backed up by 5 servers, total of 33M files. Several of the volumes are almost 2TB with several million files and all of the problems associated with that. So the windows guy is moving all of this to CIFS and we'll (hopefully) end up with several smaller volumes.
We did some testing using TSM 6.1.3.4 and NDMP full/diff to TS1120 tape. Backup times for 2 of the 3 test volumes was not that great, around 18MB/sec. The third volume backed up in half the time. According to the Netapp guy, some kind of contention/hotspot on the filer. This is backing up filer-server, not filer-tape. And filer-server allows you to do all of the traditional housekeeping tasks on the storage pools. Looked like it would be doable, until we added up all of the problems: 1. As mentioned elsewhere, the differentials, though just a fraction of the fulls estimate their size as the same as the fulls, so disk pools for the differentials were out, meaning all of the dozens of differentials every night would need a tape drive. A big scheduling headache, but not a show-stopper. 2. We tested TOC to get individual file restore capability. Performance was terrible; over an hour to restore one 50MB file. Only good news here is that increasing the size and number of files restored did not have an equivalent increase in restore time and the proposal was to keep enough snapshots to restore back two weeks. So the individual restore would be a last resort. 3. It appeared the tape compression on NDMP data was not nearly as good as on normal backups, leading to an increase in the number of tapes needed. 4. You will need a filer at your DR site to perform restores there. There was not enough upside to counteract the downsides for us, so we are going to use the SNAPDIFF feature for this application and use NDMP for a couple of big applications that were using image backups. NDMP ended up being over twice as fast for these. Sam Sheppard San Diego Data Processing Corp. (858)-581-9668 -----Original Message----- From: ADSM: Dist Stor Manager [mailto:ads...@vm.marist.edu] On Behalf Of Schaub, Steve Sent: Wednesday, June 23, 2010 8:40 AM To: ADSM-L@VM.MARIST.EDU Subject: [ADSM-L] NAS vs traditional fileservers We currently use traditional windows fileservers, but are being presented with an "opportunity" to start using a NAS device. I've been reading up on NDMP, doesn't sound to me like NAS is the backup admin's friend. Can anyone who has gone down this road share any of the biggest pros/cons/gotchas? I seem to recall from several years ago that getting the backup data offsite was an issue, but the NAS vendor claims this is no longer true. Currently using half a dozen fileservers to manage about 20TB of user data. Thanks, Steve Schaub Systems Engineer, Windows BlueCross BlueShield of Tennessee ----------------------------------------------------- Please see the following link for the BlueCross BlueShield of Tennessee E-mail disclaimer: http://www.bcbst.com/email_disclaimer.shtm
