Tim Cook writes: > On Tue, Aug 4, 2009 at 7:33 AM, Roch Bourbonnais > <roch.bourbonn...@sun.com>wrote: > > > > > Le 4 août 09 à 13:42, Joseph L. Casale a écrit : > > > > does anybody have some numbers on speed on sata vs 15k sas? > >>> > >> > >> The next chance I get, I will do a comparison. > >> > >> Is it really a big difference? > >>> > >> > >> I noticed a huge improvement when I moved a virtualized pool > >> off a series of 7200 RPM SATA discs to even 10k SAS drives. > >> Night and day... > >> > >> > > If by 'huge' you mean much more than 10K/7.2K in the data path with > > otherwise same number of spindles, then > > that has got to be because of something not specified here. > > > > -r > > > > No it doesn't. The response time on 10k drives is night and day better than > 7.2k drives. VMware workloads look exactly like DB workloads. Faster > spindles=better response time=virtualized platform being much happier. >
Yes, at light thread count and to the tune of 10K/7.2K. At high load, if you're demand exceeds the supply, then there is no bounds to what response time will be. To make a fair comparison, I would pit 2 systems with about the same total RPM. > Not to mention, in my experience, the 7.2k drives fall off a cliff when you > overwork them. 10k/15k drives tend to have a more linear degradation in > performance. > That's the 'something else'. It's got to be in the driver/firmware not in the RPM/Interface protocol. -r > --Tim _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
