On Wed, Jan 7, 2009 at 2:02 PM, Stefano Nichele <stefano.nichele@xxxxxxxxx> wrote: > > On Tue, Jan 6, 2009 at 7:45 PM, Scott Marlowe <scott.marlowe@xxxxxxxxx> > wrote: >> >> I concur with Merlin you're I/O bound. >> >> Adding to his post, what RAID controller are you running, does it have >> cache, does the cache have battery backup, is the cache set to write >> back or write through? > > > At the moment I don't have such information. It's a "standard" RAID > controller coming with a DELL server. Is there any information I can have > asking to the SO ? You can run lshw to see what flavor controller it is. Dell RAID controllers are pretty much either total crap, or mediocre at best. The latest one, the Perc 6 series are squarely in the same performance realm as a 4 or 5 year old LSI megaraid. The perc 5 series and before are total performance dogs. The really bad news is that you can't generally plug in a real RAID controller on a Dell. We put an Areca 168-LP PCI-x8 in one of our 1950s and it wouldn't even turn on, got a CPU Error. Dells are fine for web servers and such. For database servers they're a total loss. The best you can do with one is to put a generic SCSI card in it and connect to an external array with its own controller. We have a perc6e and a perc5e in two different servers, and no matter how we configure them, we can't get even 1/10th the performance of an Areca controller with the same number of drives on another machine of the same basic class as the 1950s. >> Also, what do you get for this (need contrib module pgbench installed) >> >> pgbench -i -s 100 >> pgbench -c 50 -n 10000 >> >> ? Specifically transactions per second? > > I'll run pgbench in the next days. Cool. That pgbench is a "best case scenario" benchmark. Lots of small transactions on a db that should fit into memory. If you can't pull off a decent number there (at least a few hundred tps) then can't expect better performance from real world usage. Oh, and that should be: pgbench -c 50 -t 10000 not -n... not enough sleep I guess. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
