I would recommend running a bonnie++ benchmark on your array to see if it's the array/controller/raid being crap, or wether it's postgres. I have had some very surprising results from arrays that theoretically should be fast, but turned out to be very slow.
I would also seriously have to recommend against a 14 drive RAID 5! This is statisticaly as likely to fail as a 7 drive RAID 0 (not counting the spare, but rebuiling a spare is very hard on existing drives). Alex Turner netEconomist On Fri, 11 Mar 2005 16:13:05 -0500, Arshavir Grigorian <[EMAIL PROTECTED]> wrote: > Hi, > > I have a RAID5 array (mdadm) with 14 disks + 1 spare. This partition has > an Ext3 filesystem which is used by Postgres. Currently we are loading a > 50G database on this server from a Postgres dump (copy, not insert) and > are experiencing very slow write performance (35 records per second). > > Top shows that the Postgres process (postmaster) is being constantly put > into D state for extended periods of time (2-3 seconds) which I assume > is because it's waiting for disk io. I have just started gathering > system statistics and here is what sar -b shows: (this is while the db > is being loaded - pg_restore) > > tps rtps wtps bread/s bwrtn/s > 01:35:01 PM 275.77 76.12 199.66 709.59 2315.23 > 01:45:01 PM 287.25 75.56 211.69 706.52 2413.06 > 01:55:01 PM 281.73 76.35 205.37 711.84 2389.86 > [snip] ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
