I would say you can do it good (TSM) or better as suposed by Orville.
I do not see any reason why TSM should not take advantage of the mirrored
disk's for db reading.
> -----Ursprüngliche Nachricht-----
> Von: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] Im
> Auftrag von Richard Sims
> Gesendet: Mittwoch, 25. April 2007 17:49
> An: ADSM-L AT VM.MARIST DOT EDU
> Betreff: Re: TSM only reads from COPY1 during DB backup
> On Apr 25, 2007, at 10:55 AM, Orville Lantto wrote:
> > Reads should be safe from mirrored volumes and are commonly done in
> > operating systems to load balance. Not taking advantage of the
> > available IO resource is wasteful and puts an unnecessarily
> > unbalanced load on an already IO stressed system. It slows down db
> > backups too.
> Then your issue is performance, rather than database voracity.
> This is addressed by the disk architecturing chosen for the TSM
> database, where raw logical volumes and RAID on top of high
> performance disks accomplishes that. Complementary volume striping
> largely addresses TSM's symmetrical mirror writing and singular
> reading. Whereas TSM's mirroring is an integrity measure rather then
> performance measure, you won't get full equivalence from that.
> Another approach, as seen in various customer postings, is to employ
> disk subsystem mirroring rather than TSM's application mirroring. In
> that way you get full duality, but sacrifice the protections and
> recoverability which TSM offers.
> Richard Sims