Hell, Robert wrote:
> We have a PostgreSQL 8.2.7 database (~230 GB) running on a machine with 8 Intel Xeon Cores and 32 GB RAM (64-bit Linux 2.6.18). Data is stored on an EMC² CLARiiON on RAID 1/0 (8 x 146 GB 15k rpm).
> When we do random I/O with a small test tool (reading random 8k blocks from big files in 200 threads) on the disk we retrieve data with about 25 MB/s.
How do you test random IO? Do you use this utility:
http://arctic.org/~dean/randomio/ ?
If not, try using it, with same parameters. It might be that the latency
is destroying your performance. Do you use NFS or are you accessing the
storage as SAN?