On Mon, Jan 11, 2010 at 2:59 PM, Greg Smith <greg@xxxxxxxxxxxxxxx> wrote: > Scott Marlowe wrote: > If you can shoehorn one more drive, you could run RAID-10 and get much > better performance. > > > And throwing drives at the problem may not help. I've see a system with a > 48 disk software RAID-10 that only got 100 TPS when running a commit-heavy > test, because it didn't have any way to cache writes usefully for that > purpose. A 4 disk RAID-10 will be about 4 to 8 times faster than a RAID-5 of 3 disks. It won't be as fast as a good sized RAID-10 with HW caching, but it would be a big improvement. > If the old system had a write caching card, and the new one doesn't, that's > certainly your most likely suspect for the source of the slowdown. As for Agreed. If the new machine is limited to 3 disks, and any one is big enough to hold the db, I'd look at a two disk mirror with a hot spare on a HW RAID controller with battery backed chat. If they can't get a HW RAID controller than switching to SW RAID-1 would be a positive step. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
