> >> dd if=/dev/zero of=test.txt bs=8192 count=1310720 conv=fdatasync >> 10737418240 bytes (11 GB) copied, 169.482 s, 63.4 MB/s >> >> dd if=test.txt of=/dev/null bs=8192 >> 10737418240 bytes (11 GB) copied, 86.4457 s, 124 MB/s > > These look slow. RAID5 isn't going to be amazing, but it should be > better than this. I'd spend some more time optimizing your system > config before worrying about PG. If I can read at 90MB/s from a single > stock SATA drive you should be almost hitting 200MB/s with this, or > 300MB/s in a RAID1 across three drives.
They are slow, they are not atypical for RAID5; especially the slow writes with SW RAID-5 are typical. I'd try a simple test on a 2 or 3 disk RAID-0 for testing purposes only to see how much faster a RAID-10 array of n*2 disks could be. The increase in random write performance for RAID-10 will be even more noticeable. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
