On Apr 25, 2010, at 10:02 PM, Dave Pooser wrote: > 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?
For a single connection from a host to a disk, they are basically equivalent. SAS shines with multiple connections to one or more hosts. Hence, SAS is quite popular when implementing HA clusters. Note: drive differentiation is market driven, not technology driven. -- richard ZFS storage and performance consulting at http://www.RichardElling.com ZFS training on deduplication, NexentaStor, and NAS performance Las Vegas, April 29-30, 2010 http://nexenta-vegas.eventbrite.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
