On Tue, 2005-08-16 at 10:46 -0700, Roger Hand wrote: > The disks are ext3 with journalling type of ordered, but this was later > changed to writeback with no apparent change in speed. > > They're on a Dell poweredge 6650 with LSI raid card, setup as follows: > 4 disks raid 10 for indexes (145GB) - sdc1 > 6 disks raid 10 for data (220GB) - sdd1 > 2 mirrored disks for logs - sdb1 > > stripe size is 32k > cache policy: cached io (am told the controller has bbu) > write policy: write-back > read policy: readahead
I assume you are using Linux 2.6. Have you considered booting your machine with elevator=deadline? You can also change this at runtime using sysfs. These read speeds are not too impressive. Perhaps this is a slow controller. Alternately you might need bigger CPUs. There's a lot of possibilities, obviously :) I'd start with the elevator, since that's easily tested. -jwb ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match