Find ! Dell CERC SATA RAID 2 PCI SATA 6ch
Running lspci -v: 03:09.0 RAID bus controller: Adaptec AAC-RAID (rev 01) Subsystem: Dell CERC SATA RAID 2 PCI SATA 6ch (DellCorsair) Flags: bus master, 66MHz, slow devsel, latency 32, IRQ 209 Memory at f8000000 (32-bit, prefetchable) [size=64M] Expansion ROM at fe800000 [disabled] [size=32K] Capabilities: [80] Power Management version 2 Any consideration looking at iostat output ? Cheers and thanks to all! ste On Wed, Jan 7, 2009 at 10:31 PM, Scott Marlowe <scott.marl...@gmail.com>wrote: > On Wed, Jan 7, 2009 at 2:02 PM, Stefano Nichele > <stefano.nich...@gmail.com> wrote: > > > > On Tue, Jan 6, 2009 at 7:45 PM, Scott Marlowe <scott.marl...@gmail.com> > > 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. >