On 3/25/09 1:07 AM, "Greg Smith" <gsmith@xxxxxxxxxxxxx> wrote: > On Wed, 25 Mar 2009, Mark Kirkwood wrote: > >> I'm thinking that the raid chunksize may well be the issue. > > Why? I'm not saying you're wrong, I just don't see why that parameter > jumped out as a likely cause here. > If postgres is random reading or writing at 8k block size, and the raid array is set with 4k block size, then every 8k random i/o will create TWO disk seeks since it gets split to two disks. Effectively, iops will be cut in half. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
