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
