By Dave Simpson and Ann Silverthorn
In an indication that the Serial Attached SCSI (SAS) disk drive interface is ready for prime time, SGI recently became 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.
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 Logic 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.
SGI also recently began shipments of the 3U InfiniteStorage 350 RAID array, which 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 is priced from less than $30,000.
SGI’s InfiniteStorage 120 and 350 are both based on systems from LSI Logic’s Engenio division.
LSI recently rounded out its Serial Attached SCSI (SAS) and Serial ATA (SATA) adapter lines with additions for server, workstation, and enterprise storage interconnection requirements. LSI released three SAS host bus adapters (HBAs), as well as two SATA RAID adapters and a SAS zero-channel RAID (ZCR) adapter for the company’s MegaRAID product line (see table on p. 12 for models and pricing).
LSI’s HBA line features the Fusion MPT controller architecture, which puts integrated RAID and driver functions in the adapter card firmware. This uses less CPU memory and increases performance. The HBAs support RAID levels 0, 1, 1E, or 10E. (RAID 1E is enhanced mirroring, which offers the same functionality as RAID 10 on an odd number of drives, while RAID 10E is the same as RAID 1E, but on an even number of drives.)
LSI builds its own native PCI-X and PCI-Express controller chips on its HBAs instead of using bridge chips, which can degrade performance.
The MegaRAID line includes an OS-independent management suite, which allows users to manage tiered storage. In addition, two of the new MegaRAID adapters allow SAS-enabled SATA. LSI builds the SATA adapters with a common connector, cabling, and firmware, similar to the way a SAS adapter would be built. This allows users to start with a SATA adapter and upgrade to a SAS adapter without having to rebuild the related infrastructure.
LSI’s new MegaRAID SAS zero-channel RAID (ZCR) adapter plugs into SAS-enabled motherboards. The ZCR card has no SAS connectors on it, but operates over the PCI bus. It supports RAID 0, 1, 5, 10, and 50.