On Sun, 2006-01-29 at 13:44 -0500, Luke Lonergan wrote: > Depesz, > > > [mailto:pgsql-performance-owner@xxxxxxxxxxxxxx] On Behalf Of > > hubert depesz lubaczewski > > Sent: Sunday, January 29, 2006 3:25 AM > > > > hmm .. do i understand correctly that you're suggesting that > > using raid 10 and/or hardware raid adapter might hurt disc > > subsystem performance? could you elaborate on the reasons, > > please? it's not that i'm against the idea - i'm just curious > > as this is very "against-common-sense". and i always found it > > interesting when somebody states something that uncommon... > Oh - and about RAID 10 - for large data work it's more often a waste of > disk performance-wise compared to RAID 5 these days. RAID5 will almost > double the performance on a reasonable number of drives. I think you might want to be more specific here. I would agree with you for data warehousing, decision support, data mining, and similar read-mostly non-transactional loads. For transactional loads RAID-5 is, generally speaking, a disaster due to the read-before-write problem. While we're on the topic, I just installed another one of those Areca ARC-1130 controllers with 1GB cache. It's ludicrously fast: 250MB/sec burst writes, CPU-limited reads. I can't recommend them highly enough. -jwb PS: Could you look into fixing your mailer? Your messages sometimes don't contain In-Reply-To headers, and therefore don't thread properly.
