I tried different other tools for random IO (including a self written one which does random lseek and read).
This tool, started during one of our tests, achieves 2 iops (8k each). Started alone I get something about 1,500 iops with an avg latency of 100 ms. We are using SAN (EMC CLARiiON CX 300) - are those ~7 MB/s really our bottleneck? Any other tuning ideas? Regards, Robert -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ivan Voras Sent: Montag, 07. April 2008 14:38 To: pgsql-performance@postgresql.org Subject: Re: [PERFORM] Looking for bottleneck during load test 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? -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
