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Seagate Technology LLC and Micron Technology Inc. today unveiled a 12 Gbps Serial-Attached SCSI (SAS) enterprise solid-state drive (SSD) that offers capacity options of up to 4 TB and endurance choices to suit write-intensive, read-intensive and mixed-use application workloads.
The SAS SSD, which ships this month, is the first product resulting from the strategic alliance that Seagate and Micron forged in February, pairing the drive maker with one of the six major NAND flash manufacturers. The vendors are selling the SAS SSD under different labels. Seagate calls its product 1200.2 SAS SSD, while Micron labels it as its S600 Series of SAS SSDs.
Although less expensive Serial Advanced Technology Attachment (SATA) SSDs remain the most popular choice for enterprise SSDs, Seagate chose to parlay its expertise in SAS with Micron's NAND flash for their first collaborative effort, which targets enterprise and cloud use cases.
The enterprise SSD market is on pace to grow to more than $6 billion this year, and SAS SSDs are one of the fastest growing drive types, according to Jeff Janukowicz, research director at IDC, based in Framingham, Mass. He wrote via email that revenue for SAS SSDs grew more than 60% on a year-over-year basis during the first quarter.
"The [SAS] drive is best suited for external storage and server environments covering a wide range of mission-critical and I/O-intensive applications like server virtualization, databases and [online transaction processing] OLTP," Janukowicz wrote. He said the main competition for the new drives will come from Western Digital's HGST division, Samsung, SanDisk Corp. and Toshiba America Inc.
One of the main distinguishing features of the new 2.5-inch SAS SSD is that it affords customers options for capacity and endurance, which Seagate specifies in drive writes per day (DWPD). Options tailored to specific workloads include:
High Endurance (HE) -- 25 DWPD
Capacities -- 200 GB, 400 GB
Mainstream Endurance (ME) -- 10 DWPD
Capacities -- 400 GB to 3.2 TB
Light Endurance (LE) -- 3 DWPD
Capacities -- 400 GB to 3.84 TB
Highly read-intensive applications:
Scalable Endurance (SE) -- 1 DWPD
Capacities -- 1.92 TB, 3.84 TB
Kent Smith, senior director of product marketing for Seagate's flash products, said OEM customers wanted to be able to qualify a single SSD to work across different endurance categories, rather than having to qualify a particular SSD for a specific endurance level. He said all of Seagate's SAS SSDs have a five-year lifespan.
The 1200.2 SAS SSD uses enterprise multilevel cell (eMLC) NAND flash. The initial Seagate 1200 product had MLC flash, a capacity limit of 800 GB, 10 DWPD with the standard model and 25 DWPD with a high-endurance model, according to the product manual.
Greg Wong, founder and principal analyst at North York, Ont.-based Forward Insights, said there's been a trend toward lower endurance drives for mixed and read-intensive application workloads. He said in the early days of SSDs, 25 DWPD was popular due to concerns about drive endurance. Companies later tried to gain a better understanding of their workloads, and most SATA drives are now less than 1 DWPD, he noted. The SATA drives also cost less, he added.
"In the enterprise, there's pricing pressure and also a recognition that 3 DWPD may be overkill for read-intensive workloads," Wong wrote in an email. "This trend happened much earlier with SATA drives, and it's been moving to SAS and PCIe SSDs, as well."
The new dual-port SAS SSD can be configured to deliver up to 1,800 MB/s of sequential read performance when using both channels to a single host. Users also have the option to use the dual ports for high availability (HA) with failover redundancy and no single point of failure, in contrast to what they can do with single-port SATA SSDs.
"SAS SSD vendors like to quote what their throughput is if you use both ports, but I don't think that SAS users are as interested in that as they are in the redundancy," said Jim Handy, chief analyst at Objective Analysis in Los Gatos, Calif. "If they want that kind of bandwidth, then PCIe is a good way to go."
Other enterprise features in the new SAS SSDs include multi-layered error recovery technology with advanced error detection/correction encoding, power-loss protection and three security levels -- secure diagnostics and download, self-encrypting drive (SED) with Trusted Computing Group (TCG) compliance, and SED Federal Information Processing Standards (FIPS).
The 1200.2 SAS SSD is designed for OEMs and system builders, but it will also be available to enterprises that are upgrading or expanding their existing SAS storage infrastructure, according to Seagate.
SAS interface trending upward
Seagate and Micron in the PCIe SSD market