By Dave Simpson
Adapters, controllers, and subsystems based on the Serial Attached SCSI (SAS) interface-the successor to the venerable parallel SCSI interface-are rolling out in production volumes, and SAS-based servers are available from vendors such as Hewlett-Packard and IBM. Although SAS provides performance improvements over its predecessor, for some users and integrators its primary appeal is that SAS subsystems can support SAS and Serial ATA (SATA) disk drives.
And there's no question about how popular SATA is these days. In a QuickVote poll of InfoStor's readers, more than half (51%) of the respondents said that SATA drives will represent the majority of their non-desktop disk drive purchases over the next six months. Meanwhile, 11% of the respondents cited SAS (see figure).
As further evidence of the popularity of SATA, the technology was ranked number one in an end-user survey conducted by TheInfoPro research firm (www.theinfo pro.com). The survey asked users to rank 20 relatively new technologies according to the users' purchasing plans. In fact, SATA was ranked number one in each of TheInfoPro's previous three surveys, which are conducted every six months.
In the initial adoption stages, SAS disk drives will be found primarily in servers with direct-attached storage configurations. As adoption picks up, users are expected to opt for external SAS-based storage subsystems that may include a mix of SAS and SATA drives for "in-the-box" tiered storage that combines the high performance and reliability of SAS drives with low-cost, high-capacity (up to 500GB) SATA drives.
Here's a quick recap of some of the SAS/SATA products that began shipping recently:
This month, Adaptec began production shipments of seven SAS products, including a host bus adapter (HBA), two controllers, an enclosure, two external subsystems, and software.
Adaptec's 48300 HBA includes eight 3Gbps SAS or SATA ports, 1x4 internal and external connectors, support for the 64-bit 133MHz PCI-X host bus, HostRAID and management software, and support for RAID levels 0, 1, 10, and JBOD configurations. The adapter is priced at $360, which is about the same as Adaptec's high-end parallel SCSI adapters.
The 4800SAS (PCI-X, priced at $945) and 4805SAS (PCI-Express, priced at $995) RAID controller cards have up to eight SAS or SATA ports via 2x4 internal connectors, external connectors to JBOD systems, 128MB of cache, up to 512TB of RAID capacity, and all of the features available on Adaptec's parallel SCSI controller cards.
Adaptec's 335SAS enclosure ($350 without disk drives) includes four 3.5-inch bays for SAS or SATA drives and support for all of the company's SAS and SATA II RAID cards (up to two enclosures per RAID card).
On the software front, Adaptec introduced the Advanced Data Protection Suite, which includes support for RAID 6, striped mirrors, online snapshot backup, and a Hot Space feature that spreads the hot spare disk space across the array to increase performance and better utilize capacity.
Finally, Adaptec introduced two external subsystems-the SANbloc 5000f RAID array and SANbloc S50 JBOD array. Priced at $5,995 without drives, the SANbloc 500f is a 12-drive Fibre Channel-to-SAS array with up to 64,000 I/Os per second and 440MBps read performance, according to the company. The SANbloc S50, priced at $2,995 without drives, is a 12-drive SAS-to-SAS JBOD array.
LSI-which has SAS-related OEM deals with vendors such as Dell, Hewlett-Packard, Fujitsu Siemens, and Sun-is shipping to the channel its dual-port, eight-channel, 3Gbps SAS3442X HBAs for PCI-X systems. The HBA is priced at $367, or $1,275 for a five-pack with cables.
LSI is also shipping the 8-port MegaRAID SAS 8408E internal RAID adapter/controller for PCI-Express systems. The 8408E includes a battery-backed 256MB cache module that enables administrators to replace a failed adapter while maintaining the data protected for up to 72 hours.
In addition, LSI is shipping 28-port and 36-port SAS expanders that can auto-sense between 1.5Gbps and 3Gbps speeds. The expanders are based on a non-blocking crossbar switch architecture and ARM processors. The company plans to introduce a number of new SAS/SATA adapters in the next quarter.
Infortrend's EonStor (ES) S12F-R1420 is a 4Gbps Fibre Channel-to-SAS RAID subsystem that the company claims can deliver more than 1GBps throughput in sequential read operations. The subsystem includes support for hardware-based RAID 6, a 600MHz PowerPC FX CPU, PCI-X bus support, 12 drive channels, 2GB of cache, dual RAID controllers and Fibre Channel ports, and field-replaceable components. The array has been tested with SAS drives from Fujitsu and Seagate.
For greater capacity, Infortrend offers the ES S12S-J1000 SAS-to-SAS JBOD subsystem with redundant SAS expander boards and support for as many as 128 drives.
Promise Technology this month began shipments of an external SAS subsystem in a JBOD configuration. The VTrack J-Class J300s systems mark the company's first entry into the enterprise subsystem market. Initial shipments support SAS drives, with support for SATA expected in the first or second quarter of next year.
The 2U J300s has dual SAS host ports plus a SAS expander port for cascading up to four subsystems, 12 3.5-inch drive bays, redundant modules, a SAS expander chip from PMC-Sierra, and user-selectable SAS cable lengths (1 meter to 10 meters). The J-Class subsystems have been tested with drives from Fujitsu, Hitachi, Maxtor, and Seagate.
On the SATA front, AMCC is shipping RAID controllers with support for the Serial ATA 2.5 specification and PCI-X hosts. The 3ware 9550SX family is based on the company's StorSwitch non-blocking switched fabric architecture. The company claims RAID-5 write performance of more than 380MBps and RAID-5 read performance of more than 800MBps. SATA II features include 3Gbps speed, native command queuing (NCQ), port selection, and port multiplication. A 4-port 9550SX-4P controller and an 8-port version (9550SX-8LP) are priced at $395 and $595, respectively. A 12-port version is expected to be priced at $795, and a 16-port board at $995. The controllers support up to 8TB using 500GB SATA drives.
Seagate is shipping the 500GB, 7,200rpm Barracuda 7200.9 series of disk drives with support for the SATA 2.5 spec. The 3Gbps drives include 16MB of cache, NCQ, Intel Hyper-Threading for increased performance, command re-ordering, and interrupt aggregation. Seagate's SATA drives range from 80GB to 500GB.
At the Storage Networking World conference last month, Maxtor introduced SATA II (and ATA/133) disk drives as members of the company's MaXLine (enterprise applications), DiamondMax (desktop), and QuickView (for consumer electronics devices) product lines. Features include a rotation rate of 7,200rpm, 16MB buffer, and SATA II features such as NCQ, staggered spin-up, hot-plug, and asynchronous signal recovery.
The MaXLine Pro 500 SATA II drives include a number of performance and reliability features, such as rotational vibration compensation, accelerated error recovery, and expanded drive self-test. Maxtor is also shipping a full line of Atlas SAS drives.