On Tue, Mar 07, 2006 at 08:49:30PM +0100, Joost Kraaijeveld wrote: > > Jim C. Nasby wrote: > > > Speaking of 'disks', what's your exact layout? Do you have a 5 drive > > raid5 for the OS and the database, 1 drive for swap and 1 drive for > > pg_xlog? > > On a Sil SATA 3114 controller: > /dev/sda OS + Swap > /dev/sdb /var with pg_xlog > > On the 3Ware 9500S-8, 5 disk array: > /dev/sdc with the database (and very safe, my MP3 collection ;-)) > > As I wrote in one of my posts to Michael, I suspect that the card is not > handling the amount of write operations as well as I expected. I wonder if > anyone else sees the same characteristics with this kind of card.
Well, the problem is that you're using RAID5, which has a huge write overhead. You're unlikely to get good performance with it. Also, it sounds like sda and sdb are not mirrored. If that's the case, you have no protection from a drive failure taking out your entire database, because you'd lose pg_xlog. If you want better performance your best bets are to either setup RAID10 or if you don't care about the data, just go to RAID0. -- Jim C. Nasby, Sr. Engineering Consultant [EMAIL PROTECTED] Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461 ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
