----- "Dave Pooser" <dave....@alfordmedia.com> skrev: > I'm building another 24-bay rackmount storage server, and I'm > considering > what drives to put in the bays. My chassis is a Supermicro SC846A, so > the > backplane supports SAS or SATA; my controllers are LSI3081E, again > supporting SAS or SATA. > > Looking at drives, Seagate offers an enterprise (Constellation) 2TB > 7200RPM > drive in both SAS and SATA configurations; the SAS model offers one > quarter > the buffer (16MB vs 64MB on the SATA model), the same rotational > speed, and > costs 10% more than its enterprise SATA twin. (They also offer a > Barracuda > XT SATA drive; it's roughly 20% less expensive than the Constellation > drive, > but rated at 60% the MTBF of the others and a predicted rate of > nonrecoverable errors an order of magnitude higher.) > > Assuming I'm going to be using three 8-drive RAIDz2 configurations, > and > further assuming this server will be used for backing up home > directories > (lots of small writes/reads), how much benefit will I see from the > SAS > interface?
We haver a similar system, SuperMicro 24-bay server with 22x2TB (and two SSDs for the root) configured as three RAIDz2 sets with seven drives each and a spare. We chose 'desktop' drives, since they offer (more or less) the same speed and with that redundancy, the chance for pool failure is so low, I guess 'enterprise' drives wouldn't help a lot more. About SAS vs SATA, I'd guess you won't be able to see any change at all. The bottleneck is the drives, not the interface to them. roy _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
