I'd suggest using TSM to back the data up to LTO, then back up the LTO storage pool to a copy pool and send the copies off-site. Run reclaims and only bring back empty or pending empty off-site tapes. My worst case sends off a tape that is 5% full daily. The reclaim actually kicks in just after the tapes are checked out. The downside to this is the number of $110 LTO tapes you need, and that's a function of how often you move tapes off-site and how often you bring back the empties.
You don't need DRM for this, although it may help (never tried it, so I can't help there). I've got a few conventions I use and a few scripts that simplify life, and we ship off-site daily, with the empties coming back on Friday. The naming convention I use is <poolname> as diskpool, <poolname>-LT as tape pool, and <poolname>-LT-COPY as copy pool: INDEF (disk pool for our commonstore), INDEF-LT, and INDEF-LT-COPY. One of the daily scripts does the backup storage pool. Another does a "q vol stg=*copy acce=reado,readw st=fil,ful", captures the volsers and does the "checkout libvol <library> <volser> remove=bulk checklabel=no". A typical day sees 8 tapes going off-site, including the TSM database backup; a normal Friday has 40 tapes coming back, including 5 week-old TSM database backups. Hope this helps - Tom Kauffman NIBCO, Inc > -----Original Message----- > From: Justin Derrick [mailto:[EMAIL PROTECTED]] > Sent: Thursday, January 24, 2002 8:06 AM > To: [EMAIL PROTECTED] > Subject: Mitigating Risk with TSM's incremental backups > > > I've been using TSM for quite a few years on AIX, and > surprisingly, this > issue hasn't come up before. > > My customer is using TSM in conjunction with Content Manager > OnDemand. The > config looks like this: > > AIX 4.3.3 on H70 > OnDemand, DB2, TSM > Data is cached on disk (by OnDemand, not TSM), and also > copied to Optical > (a la 3995), then backed up to LTO. > They are currently a very low-volume shop, adding under 1GB a > day to the > TSM system. > > The question raised to which I didn't have a good answer was: > > If we take a non-full LTO offsite for disaster recovery purposes, then > bring it back onsite as part of regular rotation, a vulnerability is > created. If the tape is on site when a disaster occurs > (which would always > be the case since their courier only delivers once a day), > not only is that > day's information lost, but all the previous days of incrementals > previously written to the tape are destroyed as well. > > I know we could keep multiple copypools in the chain, but it > seems like an > expensive solution to a simple problem. > > The immediate solution would be to create new 'full' backups of the > contents of the optical jukebox every day, and take them > offsite. While > this would actually be feasible in the short term (given > their low growth) > it would quickly become unmanagible in the future. > > Is the solution to simply buy enough tapes so that you simply > send one tape > a day offsite for as long as possible, then perform large > reclaimation once > every 'long as possible'? This sounds like it's within the > realm of the > DRM, which I'm woefully inexperienced with. Any advice, > direction, etc. > would be greatly appreciated. > > -JD. >
