Disks are doing 150 read + 90 write ops/s when they should be able to do a total of 1000 iops each as currently configured (this is the max that can be set). Total bandwidth is 1000mb/s each too. So clearly, either there is something wrong with ZFS/FreeBSD on Amazon (either because of config or something deeper) or PostgreSQL is not fully utilizing the hardware, again because of config or some other issue.
I will make another test instance with pg 9.2 this time. Concerning shared_buffers and wal_buffers, I found this article interesting: http://rhaas.blogspot.ca/2012/03/tuning-sharedbuffers-and-walbuffers.html Sébastien On Thu, Sep 13, 2012 at 5:28 PM, John R Pierce <pie...@hogranch.com> wrote: > On 09/13/12 2:08 PM, Sébastien Lorion wrote: > >> I started db creation over, this time with 16GB maintenance_work_mem and >> fsync=off and it does not seem to have a great effect. After again 5 hours, >> during index creation, disk and cpu are barely used: 95% idle and 2-3 MB/s >> writes (150 reads/s, 90 writes/s). >> > > I've never had to set maintenance_work_mem any higher than 1gb for plenty > good enough performance. > > whats the %busy on the disk ? if you have a slow disk device (such as a > shared virtual disk), 90 write/sec may be all its good for. MB/s is fairly > meaningless when dealing with random committed writes. > > > > > > > -- > john r pierce N 37, W 122 > santa cruz ca mid-left coast > > > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/**mailpref/pgsql-general<http://www.postgresql.org/mailpref/pgsql-general> >
