Seagate ships slim, fast Pulsar XT SSD
Slower, fatter version in the wings
Seagate is shipping its Pulsar XT.2 SSD with an SPC-1C benchmark rating, and has a second slower but higher capacity SSD coming soon.
The 2.5-inch Pulsar XT.2 is available in up to 400GB capacities, has a 6Gbit/s SAS interface, and is built from fast single-level–cell flash. Seagate submitted the drive to the SPC benchmark organisation, which recorded results in the somewhat underused SPC-1C section for components, which is further subdivided into two small storage subsystem components, one that looks at energy use and one that doesn't, plus a third component for single storage device configurations.
The Pulsar XT.2 recorded 20,008.82 SPC-1C IOPS at a cost-per-IOPS of $0.32. By comparison, a 500GB Seagate Barracuda recorded 180.48 SPC-IC IOPS at a cost/IOPS of $2.50. No surprises there – but since the new Seagate drive is the only SSD to have been tested in this way by the SPC, comparisons with other SSDs are impossible.
Seagate has a second SSD coming on July 29, the Pulsar.2, which uses slower two-bit multi-level–cell flash. This drive holds from 100GB to 800GB in its 2.5-inch, hot-pluggable form factor, and has support for both SAS and SATA 6Gbit/s interfaces. There's also an encryption option on the 800GB model.
The Pulsar.2's lifespan is defined in terms of the total amount of data that can be written to it: 15 petabytes. Seagate's data sheet says that the device has "advanced media-management technology and (SAS interface only) Protection Information, plus background media scanning, power-loss data protection, I/O error detection and correction, garbage collection techniques and wear-levelling algorithms." Unfortunately, however, it doesn't provide any quantifiable information to detail those assertions.
Neither does the company provide any performance information – no info on random read and write IOPS, nor on sequential read and write bandwidth. Ditto price. Without this info, we can't compare these Pulsars to other SSDs, such as ones from Intel and STEC, in any meaningful, quantifiable way. We can only assume that OEMs – the Pulsar.2's target customers – will get all this information, however ®
SAS vs SATA, SLC vs MLC
SAS drives do cost more than SATA, which I suppose is the reason for the much-more-expensive-than-ebay price for the Barracuda. And SLC per GB prices don't seem to be moving down much, so the price is always going to be very high compared to MLC offerings. And then there is the enterprise markup compared to consumer offerings, which can probably be seen in a comparison with the also-SLC Intel 311 drive.
how do they reach $2.50/IOPS for the Seagate Barracuda? A quick search says there's a 500GB 7200rpm SATA3 Barracuda @ $49 from Amazon, even cheaper from Ebay ~= $0.32/IOPS @ 180 IOPS coincidentally :-)
Even to reach $150 the Barracuda is SATA6 7200rpm 2TB, 64MB cache so someone's been shopping at Harrods :-D
Agreed: SAS vs SATA, SLC vs MLC
SAS is more expensive than SATA... and a quick Google for a SAS Barracuda price check gave a spread of between $175 and $295 (non-refurb) vs. $89 (list of $136) for the equivalent sized SATA.
Current MLC is 2-layer, so just from a silicon real estate standpoint we're talking double the cost for SLC for equivalent process size and storage.
So if we say 2x for SAS vs. SATA, 2x for SDD vs. HDD, and 2x for SLC vs. MLC... no disagreement that these drives should be in the 8x range for "Enterprise" grade SSD vs. "Consumer" grade HDD (yeah, I know those are debatable terms so sorry) storage... that I can understand.
16x... that I don't get. Maybe my maths are off(?)