Is iostat data normal for PostgreSql?

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http://serverfault.com – I have db server with PostgreSQL 8.4 running on it. Server has 8G RAM, Intel Core2 Quad CPU Q9300 @ 2.50GHz At one moment server becomes slow, load average was 20-40. So we bought new ssd disk 160GB and mounted it to /ssd. After that changed data_directory = '/ssd/postgresql/8.4/main' from data_directory = '/var/lib/postgresql/8.4/main' and had copied data from /var/lib/postgresql/8.4/main to /ssd/postgresql/8.4/main And now load average isn't high then 10. So it isn't well. I see data iostat: avg-cpu: %user %nice %system %iowait %steal %idle 41.93 0.00 10.29 1.08 (HowTos)