> -----Original Message----- > From: pgsql-performance-owner@xxxxxxxxxxxxxx [mailto:pgsql-performance- > owner@xxxxxxxxxxxxxx] On Behalf Of Greg Smith > Sent: Wednesday, August 17, 2011 3:18 PM > To: pgsql-performance@xxxxxxxxxxxxxx > Subject: Re: Raid 5 vs Raid 10 Benchmarks Using bonnie++ > > On 08/17/2011 02:26 PM, Ogden wrote: > > I am using bonnie++ to benchmark our current Postgres system (on RAID > > 5) with the new one we have, which I have configured with RAID 10. > The > > drives are the same (SAS 15K). I tried the new system with ext3 and > > then XFS but the results seem really outrageous as compared to the > > current system, or am I reading things wrong? > > > > The benchmark results are here: > > http://malekkoheavyindustry.com/benchmark.html > > Congratulations--you're now qualified to be a member of the "RAID5 > sucks" club. You can find other members at > http://www.miracleas.com/BAARF/BAARF2.html Reasonable read speeds and > just terrible write ones are expected if that's on your old hardware. > Your new results are what I would expect from the hardware you've > described. > > The only thing that looks weird are your ext4 "Sequential Output - > Block" results. They should be between the ext3 and the XFS results, > not far lower than either. Normally this only comes from using a bad > set of mount options. With a battery-backed write cache, you'd want to > use "nobarrier" for example; if you didn't do that, that can crush > output rates. > To clarify maybe for those new at using non-default mount options. With XFS the mount option is nobarrier. With ext4 I think it is barrier=0 Someone please correct me if I am misleading people or otherwise mistaken. -mark -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
