On Thu, Jan 27, 2011 at 10:54 AM, Stephen Frost <sfrost@xxxxxxxxxxx> wrote: > * Michael Kohl (michael.kohl@xxxxxxxxxx) wrote: >> HDD: 2x 120 GB OCZ Vertex 2 SSD; RAID 1 > > I'm amazed no one else has mentioned this yet, but you should look into > splitting your data and your WALs. Obviously, having another set of > SSDs to put your WALs on would be ideal. Actually spinning media would be a better choice. A pair of fast 15krpm drives in a mirror will almost always outrun an SSD for sequential write speed. Even meh-grade 7200RPM SATA drives will win. > You should probably also be looking into adjustments to the background > writer. It sounds like you're getting hit by large checkpoint i/o > (if you turn on logging of that, as someone else suggested, you'll be > able to corrollate the times), which can be helped by increasing the > amount of writing done between checkpoints, so that the checkpoints > aren't as big and painful. That can be done by making the background > writer more aggressive. This++. Increasing checkpoint segments can make a huge difference. We run 64 segments in production and it's a world of difference from the stock setting. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
