On May 9, 2011, at 4:50 PM, Merlin Moncure wrote:
>
> hm, if it was me, I'd write a small C program that just jumped
> directly on the device around and did random writes assuming it wasn't
> formatted. For sequential read, just flush caches and dd the device
> to /dev/null. Probably someone will suggest better tools though.
>
> merlin
>
<shameless plug>
http://pgfoundry.org/projects/pgiosim
it is a small program we use to beat the [bad word] out of io systems.
it randomly seeks, does an 8kB read, optionally writes it out (and
optionally fsyncing) and reports how fast it is going (you need to
watch iostat output as well so you can see actual physical tps without
hte OS cache interfering).
It goes through regular read & write calls like PG (I didn't want to
bother with junk like o_direct & friends).
it is also now multithreaded so you can fire up a bunch of random read
threads (rather than firing up a bunch of pgiosims in parallel) and
see how things scale up.
--
Jeff Trout <jeff@jefftrout.com>
http://www.stuarthamm.net/
http://www.dellsmartexitin.com/