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:jderrick AT CANADA DOT COM]
> Sent: Thursday, January 24, 2002 8:06 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> 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.
>
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