On Oct 9, 2012, at 2:44 AM, Claudio Freire <klaussfreire@xxxxxxxxx> wrote: > On Mon, Oct 8, 2012 at 7:25 PM, Craig James <cjames@xxxxxxxxxxxxxx> wrote: >>>> But why? What have I overlooked? >>> >>> Do you have readahead properly set up on the new one? >> >> >> # blockdev --getra /dev/sdb1 >> 256 > > > It's probably this. 256 is way too low to saturate your I/O system. > Pump it up. I've found 8192 works nice for a system I have, 32000 I > guess could work too. This, i also suggest to rebenchmark with increased wal_buffers. May be that downscale comes from wal mutex contention. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
