Hitachi Kicks Out Two 15K SAS Disks
October 26, 2009 Timothy Prickett Morgan
Hitachi‘s Global Storage Technologies, the division of the Japanese tech giant that ate IBM‘s disk drive business a few years back, has kicked out two new Serial Attached SCSI (SAS) disks that spin at 15K RPMs, and one of them is in a 2.5-inch form factor. This means Hitachi’s server OEM customers (and therefore end users buying servers) no longer have to resort to fatter and hotter 3.5-inch drives to get 15K RPM performance.
If late 2007 was when SAS drives in the small form factor went mainstream, then it looks like late 2009 is when these drives will reach the tipping point where 2.5-inch drives will be used almost exclusively in production servers and the much more capacious 3.5-inch SAS and SATA drives will be relegated to desktops and archival jobs where capacity is more important than speed or the physical size of the disk drive.
Provided that IBM is still sourcing disk drives from its former disk division (and there is every reason to believe that it is), the Ultrastar 15K600 will probably be making a debut in Power Systems machines at some point in the not-too-distant future. This is a 3.5-inch form factor drive with 600 GB of capacity that has 33 percent more capacity than the 450 GB Hitachi disk it replaces in the 15K lineup. The Ultrastar 15K600 will be offered with 6 Gb/sec SAS and 4 Gb/sec Fibre Channel interfaces, and the extra capacity in the unit is made possible because Hitachi has added one more disk platter and two more disk heads to the drive. Hitachi will also be offering 450 GB units (three platters and six heads) and 300 GB units (two platters and four heads) in the Ultrastar 15K600 family. The drives have an average latency of 2 milliseconds and a seek time of 3.4 milliseconds for typical reads. The unit operates at 16.6 watts in the 600 GB capacity, which Hitachi says is 23 percent better performance than its predecessor.
If compact size and lower energy bills is more important to you, as it is for many server buyers these days, then you may find the Ultrastar C15K147 more interesting as a potential storage device for your Power server. The C15K147 is a 2.5-inch disk that spins at 15K and that has a 6 Gb/sec SAS interface. The drive is offered in a 147 GB capacity (with two platters and four heads) or a 73 GB capacity (one platter and two arms). The unit has a 2 millisecond average latency and a 3 millisecond average seek time on reads, which is also 23 percent better performance than its predecessors in the 2.5-inch SAS drive family made by Hitachi. The 147 GB version of this disk has an operating power draw of 7.3 watts, and the 73 GB version operates at 6.8 watts. That’s less than half the juice that the new 3.5-inch SAS drive above consumes as it retrieves data.
The two new SAS drives are available from Hitachi as of last week; pricing was not announced for the drives. It is unclear when and if IBM will support either unit, but I would guess that the 2.5-inch disk will end up on Power Systems boxes, and probably the 3.5-inch drive as well. IBM put some new small form factor drives in the System x servers last week, and for all I know, these were Hitachi units.