On Fri, 26 Apr 2013, James Harper <james.harper@bendigoit.com.au> wrote:
iostat while all this is going on shows pretty much nothing happening.
What does iostat show for %util? If the overall speed is low but %util is near 100% then it usually means a storage hardware problem.
I don't see a %util. This is an average sort of output of iostat 1:
Run "iostat -x 1" and you'll get it.
I'm doing a test conversion to postgresql now, although swapping back is easy enough as the old mysql database is intact. While doing the conversion which is basically a bulk insert into postgresql database, %util is indeed high - 95-100% in the VM and mostly >50% on the physical machine for both raid1 member disks, even though the iops remain low. So my first guess is that it's probably not a problem with the actual disks - both disks appear equally affected and SMART reports nothing out of the ordinary. I'll migrate some VM's and reboot the physical machine, which I thought I'd already done but uptime says otherwise. Any other suggestions? Thanks James