By Dave Simpson
In an indication that the Serial Attached SCSI (SAS) disk-drive interface is ready for prime time, SGI has become one of the first disk-systems vendors to ship SAS-based storage arrays. (Hewlett-Packard is also shipping SAS systems.) SGI also added an entry-level 4Gbps Fibre Channel array to its roster of RAID arrays.
The SAS-based InfiniteStorage 120 JBOD array has 3Gbps SAS interfaces, and replaces SGI's InfiniteStorage TP900 and D-Brick systems as the primary storage system for the company's Altix servers and clusters. In addition to Altix hosts, the disk array can connect to any host equipped with SAS adapters, and comes with one or two SAS host connections. (SGI uses SAS adapters from LSI in its Altix servers.)
The 2U model 120 includes up to 12 SAS drives per enclosure, for 3.6TB of total capacity with 300GB, 10,000rpm SAS drives. The system is also available with 73GB, 15,000rpm SAS drives. The fully redundant array is RoHS-compliant. An entry-level 146GB dual-drive configuration is priced at less than $6,000.
The company claims a throughput rate of up to 12Gbps over four 3Gbps drive channels, or approximately 4x the performance of an Ultra320 SCSI system.
For more information on the SAS interface, visit the SAS Resource Center: www.infostor.com/sas/sas_home.cfm.
Also introduced this week, SGI's 3U InfiniteStorage 350 RAID array includes up to four 4Gbps Fibre Channel host interfaces, dual controllers with 1GB of cache per controller, and up to 16 Serial ATA (SATA) disk drives. The company claims performance of up to 800MBps.
The model 350 RAID array is available in 8TB, 16TB, and 24TB capacities using 500GB SATA disk drives. The systems are compliant with the RoHS and NEBS-3 standards. An 8TB entry-level configuration starts at less than $30,000.
End users are moving more rapidly than expected to 4Gbps Fibre Channel—at least for external, as opposed to drive-level, connections. In a recent QuickVote poll of InfoStor's readers, 4% had already upgraded their entire SAN infrastructure to 4Gbps, while 32% have upgraded some of their infrastructure, and 28% will upgrade later this year.
SGI's InfiniteStorage 120 and 350 are both based on technology from LSI's Engenio division.
Now that SGI offers storage systems based on SAS, Fibre Channel, or SATA drives, how does the company position the options? "Fibre Channel is still the high-end performance leader, but we'll push SAS as a direct-attached replacement for SCSI," says Kurt Kuckein, a product marketing manager at SGI. "We position SATA primarily for high-capacity secondary storage."
Although SAS systems can typically accommodate both SAS and SATA disk drives, SGI's InfiniteStorage 120 is currently available only with SAS drives. "We're not comfortable putting SATA drives in a JBOD system that doesn't have RAID protection," says Kuckein.
(InfoStor Online Article--August 24, 2006)