Hello All, I have an iostat question in that one of the raid arrays seems to act differently than the other 3. Is this reasonable behavior for the database or should I suspect a hardware or configuration problem?
But first some background: Postgresql 7.4.2 Linux 2.4.20, 2GB RAM, 1-Xeon 2.4ghz with HT turned off 3Ware SATA RAID controller with 8 identical drives configured as 4 RAID-1 spindles 64MB RAM disk postgresql.conf differences to postgresql.conf.sample: tcpip_socket = true max_connections = 128 shared_buffers = 2048 vacuum_mem = 16384 max_fsm_pages = 50000 wal_buffers = 128 checkpoint_segments = 64 effective_cache_size = 196000 random_page_cost = 1 default_statistics_target = 100 stats_command_string = true stats_block_level = true stats_row_level = true The database is spread over 5 spindles: /ram0 holds the busiest insert/update/delete table and assoc. indexes for temporary session data /sda5 holds the OS and most of the tables and indexes /sdb2 holds the WAL /sdc1 holds the 2nd busiest i/u/d table (70% of the writes) /sdd1 holds the single index for that busy table on/sdc1 Lately we have 45 connections open from a python/psycopg connection pool. 99% of the reads are cached. No swapping. And finally iostat reports: Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util /dev/sda5 0.01 3.32 0.01 0.68 0.16 32.96 0.08 16.48 48.61 0.09 12.16 2.01 0.14 /dev/sdb2 0.00 6.38 0.00 3.54 0.01 79.36 0.00 39.68 22.39 0.12 3.52 1.02 0.36 /dev/sdc1 0.03 0.13 0.00 0.08 0.27 1.69 0.13 0.84 24.06 0.13 163.28 13.75 0.11 /dev/sdd1 0.01 8.67 0.00 0.77 0.06 82.35 0.03 41.18 107.54 0.09 10.51 2.76 0.21 The /sdc1's await seems awfully long compared to the rest to the stats. Jelle -- http://www.sv650.org/audiovisual/loading_a_bike.mpeg Osama-in-October office pool. ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster