SAS rollouts pick up steam

By InfoStor staff

June 15, 2006--By now, all storage integrators and users are familiar with the benefits of the Serial Attached SCSI (SAS) interface: It has better performance scalability than its parallel SCSI predecessor, it's simpler to integrate and, perhaps most importantly, users and integrators can configure SAS systems with either SAS or Serial ATA (SATA) disk drives.

But until recently there's been a paucity of products for integrators and users to choose from to get them on the road to SAS. However, that appears to be changing. As evidence of the momentum behind SAS, LSI last month announced that it had shipped more than 500,000 SAS components to the OEM market.

Here's a sampling of SAS-related products that began shipping over the last couple of months:

Last month, Adaptec added the models 44300 and 58300 to its family of HostRAID SAS controllers. Designed for low-end and midrange servers and workstations, the controller cards come in a low-profile form factor and support the 64-bit, 133Hz PCI-X host interface. Features of both controllers include support for both SAS and SATA disk drives, up to eight direct-attached drives (or up to 128 devices using SAS expanders), and support for RAID levels 0, 1, and 10. (SAS expanders allow for configurations in which multiple initiators can have connections to multiple targets.)

The lower-end model 44300 controller (priced at $250) includes one x4 (four-lane) internal connector, while the 58300 ($360) has two x4 external connectors and is designed to attach to SAS JBOD or RAID arrays. The controllers join Adaptec's HostRAID line of SAS controllers, which include 4-port and 8-port devices that support the PCI-X and PCI-Express (PCIe) host interfaces.

This month, Arena Maxtronic began shipping a variety of SAS subsystems. The SA-4342S is a 2U, eight-bay, SAS-SATA II RAID array with an Intel i80331 CPU. The SS-4551S (4Gbps Fibre Channel-SAS) and 4552S (SAS-SAS) are 2U, 12-bay RAID arrays that include an AMCC PPC440SP processor. And the SS-6651S, 6652S, and 6652J are 3U, 16-bay arrays based on AMCC's PPC440SP CPU in 4Gbps FC-SAS or SAS-SAS RAID or JBOD configurations.

Ario Data Networks recently began shipping the first two products in its Capacity Storage Array (CSA) series of SAS and SATA disk subsystems. The Capacity RAID Array (CRA) and Capacity Expansion Array (CEA) feature a front-loaded blade design that allows disk maintenance without interrupting operations. The CSA family is based on Ario's RAID controllers and JBOD SATA and SAS connectivity products.

Each 4U CSA array can hold up to 13 StorBlades that contain four SATA II or SAS drives each, for a total capacity of up to 26TB. The StorBlades are accessed from the front of the array, and in case of a failed drive Ario's SafeBlade technology stores I/Os while the blade is removed. When the blade is replaced, the system rebuilds itself in the background.

The CSA arrays have a modular design that allows expansion by swapping out the RAID controller for a JBOD controller. Users can also add I/O connectivity modules for Fibre Channel and 1Gbps or 10Gbps iSCSI.

Atto Technology has developed a line of SAS/SATA RAID adapters for PCI Express (PCIe) hosts. The low-profile ExpressSAS adapters provide up to 2.4GBps of throughput and include user-selectable port configuration options. The adapters support RAID 0/1/5/6/10/50/60 and include a DVRAID feature for applications such as 2K and 4K film, real-time effects, and high-definition video editing. The ExpressSAS RAID adapters are based on x8 PCIe technology.

Infortrends' EonStor S12F-R/G1420 arrays have one or two RAID controllers with two 4Gbps Fibre Channel host connections per controller, up to 4GB of cache, and as many as 12 3.5-inch SAS or SATA disk drives in a 2U enclosure. In a four-channel configuration with RAID 5, the company claims sequential read performance of 780MBps and sequential write performance of 521MBps. All components are redundant and hot-swappable.

Infortrends also sells the EonStor S12S-J1000, a SAS-to-SAS JBOD subsystem with redundant SAS expander boards.

Start-up Nimbus Data Systems is using LSI's SAS technology in its recently released Breeze MX4 and 10G IP SAN systems, which support SAS and SATA drives as well as iSCSI, 1Gbps or 10Gbps Ethernet, and both SAN and NAS. (For more information, see Nimbus claims iSCSI 'firsts'.)

Rasilient Systems recently began shipments of the Rastor 6000 RAID array, which supports SAS and SATA drives. The 3U array can be configured with up to three 2U, 12-bay SAS expansion JBOD arrays for capacity extension up to 51 disk drives. (Shipments of the expansion units began this month.)

Rasilient's subsystems, which are designed primarily for OEMs, can be configured for IP SAN, Fibre Channel SAN, SAS, or NAS. Other features include active-active controller fail-over and redundant, hot-swappable components.

Designed for embedded applications and OEMs in the telecommunications market, SBE's 6U SAS iBlade supports iSCSI and 8 or 16 3Gbps SAS or SATA ports on a CompactPCI-compatible board. SBE ported the PyX iSCSI software stack (with Error Recovery Level 2, or ERL2) to its HW400c/2 core-processing platform and bundled it with Astek's PMC-based SAS host adapters.

Xtore's XJ-SA26-224R-S is a 2U, high-density JBOD array that supports up to 24 2.5-inch small-form-factor (SSF) SAS or SATA disk drives for a total capacity to 3.5TB. The company claims a bandwidth of 4.8GBps. The array includes four host connections and two cascade connections for attachment to capacity expansion units. A dual expander is optional.

Advanced Industrial Computer (AIC) is shipping a number of storage enclosures that support SAS. Most recently, AIC introduced the BR-SAS28 canister for 2.5-inch SAS/SATA drives and the RMC3E-SA chassis for 3.5-inch SAS/SATA drives.

The BR-SAS28 can be configured with up to eight 2.5-inch drives for up to 1.1TB of capacity. AIC claims a bandwidth of 1.2GBps.

AIC's RMC3E SAS server chassis is a 3U, 16-bay enclosure that supports 3.5-inch SAS or SATA drives and a maximum capacity of up to 8TB with SATA drives. The company claims a bandwidth of 4.8GBps. The enclosure can be configured with an E-ATX-size or SSI EEB3.6v-compliant motherboard and up to seven host bus adapter cards.

IC manufacturer Vitesse Semiconductor this month began sampling additions to its NexSAS line of SAS expanders for OEMs. The second-generation VSC7156/57/58 expanders include features such as standard phy and address-resolved zoning, a multi-affiliation STP/SATA bridge, integrated Ethernet MACs, dynamic multi-level equalization, programmable edge rate control, and a 32-bit RISC CPU.

Also this month, Vitesse began shipments of SAS/SATA RAID-on-Chip (ROC) controllers¿the VSC7250 and VSC7251¿for the PCI Express host bus. The controllers can be configured as RAID controllers or SAS I/O controllers and include four or eight drive connections, an embedded RAID processor, RAID-5 hardware acceleration, and support for virtually all other RAID levels.

Molex is shipping a variety of SAS/SATA devices, including interconnects, guide frames, and cable assemblies that support 3Gbps and next-generation 6Gbps SAS as well as 1.5Gbps SATA and 3Gbps SATA II. The products include the iPass interconnect system, LaneLink and x4 Internal Multi-Lane connectors and cable assemblies, and x1 SATA connectors.

SAS disk drives
Seagate's most recent enterprise-class disk drive¿the Cheetah 15K.5¿is available with 3Gbps SAS, 4Gbps Fibre Channel, or Ultra320 SCSI interfaces. The 3.5-inch, 15,000rpm drives use perpendicular recording to achieve a capacity of up to 300GB. The drives are also available in 73GB and 147GB versions. Seagate claims a mean time between failure (MTBF) rating of 1.4 million hours at full duty cycle.

Hitachi Global Storage Technologies' entry in the SAS drive market is the Ultrastar 15K147, which began shipping almost a year ago and is available with either a SAS, 4Gbps Fibre Channel, or Ultra320 SCSI interface. The 15,000rpm drives have capacities of 36GB, 73GB, or 147GB, a 16MB cache, average seek time of 3.3ms, and an average latency of 2ms.

Fujitsu began production shipments of its 2.5-inch SAS drives in October 2005. The 10,000rpm drives are available in 37GB or 73GB versions. Features include a 16MB buffer, 2.99ms average latency, and a data-transfer rate of 3Gbps.

LSI ships SAS switch prototypes
In a sign that SANs based on SAS may be edging toward reality, LSI this month began shipping prototype versions of a 1U SAS switch with 36 ports. The device is based on the same crossbar switching technology used in some of LSI's processors.

Using copper cables, the switch supports connection distances up to 8 meters and is designed for workgroup or rack-mounted server-storage environments requiring support for as many as 10 servers connected to one or more SAS disk arrays.

According to Charlie Kraus, director of LSI's HBA business unit, LSI is aiming to make SAS fabrics simpler to manage than their Fibre Channel counterparts at a considerably lower price. But there are tradeoffs to consider: For example, SAS-based SANs are limited in two ways: distance and scalability.

SAS fabrics have a distance limitation of 8m, and LSI says it is only possible to build a switch with up to 100 ports.

General availability of LSI's SAS switch is slated for later this year.

LSI also sells SAS controller ICs, expander ICs, adapters, and RAID On Motherboard (ROMB) products.

This article was originally published on July 31, 2006