This morning, Micron announced their “RealSSD” P320h SSD, bringing them into the PCIe storage market for the first time. Already a leading supplier of both consumer and enterprise SATA SSDs, as well as the world’s leading supplier of NAND flash in partnership with Intel, this move puts Micron in direct competition with existing suppliers like media darling Fusion IO.
Introducing the RealSSD P320h
The RealSSD P320h SSD can be seen as a PCIe companion to the existing P300 series of enterprise SSDs, but it is much more than that. Micron brands their entire SSD line “RealSSD”, from the consumer grade C300 and C400 (which Crucial sells as the M4) to the enterprise P300. All include Micron’s own SSD controller ASICs and flash memory modules, offering greater levels of integration and profitability for the company.
The P320h seems similar to the recently introduced P300 in terms of componentry, but the PCIe interface puts it into a different realm of performance. Although Micron’s RealSSD line is lauded for its 6 Gb SATA interface, an internal PCI express card like that P320h blows the doors off any disk interface. Micron’s presentations show the P320h delivering over many times the IOPS of their already speedy P300! As demonstrated already by numerous competitors, there is no substitute to the low latency I/O performance of a PCIe card.
The RealSSD P320h will initially be offered in two models, both in the full-height half-length PCIe form factor. The 350 GB model offers slightly lower random write performance than its 700 GB big brother, but both boast massive performance numbers. Both use 34 nm SLC flash chips and are built on a 32-channel design.
The P320h delivers astonishing performance, at least in Micron’s PowerPoint illustrations. My own C300 can push 250 MB per second of sequential writes, and the enterprise class P300 is maybe a bit faster. But the P320h is rated at 2 GB per second sustained sequential write performance, nearly an order of magnitude faster. It would be difficult find an application, let alone a server, that could sustain this kind of throughput for long.
Even more important than throughput is I/O performance. SSDs like my C300 excel at servicing I/O requests, and are rated at 30,000 to 45,000 random 4K write IOPS. Again, the P300 is able to match this level of performance while providing five-year reliability for enterprise applications. But the P320h delivers nearly 350,000 4K write IOPS, besting the fastest and most expensive enterprise storage arrays in existence.
Note that all numbers in these charts are from the manufacturers’ own specification sheets: Micron P320h, Fusion I/O ioDRIVE DUO, TMS RamSan-70, LSI WarpDrive SLP-300, OCZ Z-Drive R2 e88, Virident tachIOn. I have included two of Micron’s RealSSD SATA drives for comparison purposes: Micron P300, Micron/Crucial C300.
Benchmarks should always be taken with a grain of salt, and manufacturer spec-sheet claims are doubly dubious. But Micron makes these claims, and it won’t be long before these devices are independently benchmarked.
Digging Deeper Into the Hardware: RAIN Reliability
The P320h is a first for Micron in a number of ways. Along with being their first PCIe card, it also is the first SSD to feature Micron’s so-called RAIN architecture and RealSSD Manager software. The P320h includes optimized drivers for Windows and Linux to further improve performance, but Micron is leaving it to partners to integrate the SSD with operating systems, hypervisors, or applications.
RAIN is Micron’s answer to concerns about SSD reliability in the enterprise. Although already using ultra-reliable SLC chips, the P320h introduces a raid like technology Micron calls Redundant Array of Independent NAND, or RAIN for short. Reminiscent of SandForce’s Redundant Array of Independent Silicon Elements (RAISE), RAIN arranges flash memory chips in a 7+1 arrangement to improve reliability and recoverability in the event of a failure.
Micron claims that this combination of intelligent controllers, RAIN, and SLC memory chips delivers top-notch reliability. The company measures reliability in terms of the number of full drive fills that can be sustained per day for five years. They claim that enterprise customers demand SSDs that can sustain 30 fills per day for five years, or an incredible 54,750 drive fills. That’s 25 PB of data written for 350 gig unit or 50 PB for the big 750 GB P320h!
Putting things another way, if the 700 GB P320h was pounded with sequential data at its rated maximum of 2 GB per second, it would take over nine months to wear out this drive. Just in case the customer expects to hammer on the drive constantly, they may use the RealSSD Manager software to throttle performance and ensure reliability to a given date.
PCIe SSDs like Micron’s new P320h offer mindbending performance and enterprise class reliability. Although expensive, these devices are in an entirely different league from any other storage option. Micron promises to bring the PCIe P320h to market at nearly $15 per gigabyte, a substantial discount over other PCIe SSD competitors. But the card will still cost more than $5000, making it an expensive add-on for most servers.
The challenge in enterprise storage is not delivering absolute capacity or performance any longer. Today’s challenge is making that capacity and performance available to applications and, ultimately, and users in the form of improved satisfaction or profitability. Micron is moving the ball forward on the hardware front, but my focus remains on software providers that will deliver this performance in a usable form for applications, hypervisors, and operating systems.