Fusion-io And Micron: A SSD Difference Of Opinion

Last week, I mentioned that I’d recently met with SSD add-in card pioneer Fusion-io while at SIGGRAPH. I also said in that same writeup that I regularly spoke about flash memory reliability with Micron Technology’s Dean Klein. Well, synchronicity strikes again…I happened to talk with Dean on Tuesday, about both flash memory (generally) and Fusion-io (specifically…along with other topics), in advance of yesterday’s news from Micron. The product itself was fairly predictable; the company just unveiled its P300 SSDs, enterprise-tailored variants of the C300 SSDs and the latest iteration of Micron’s multi-generation stab at this particular market. But as usual when Klein and I get to chatting, the big-picture discussion spawned by the announcement was where I found the most valuable nuggets.

As background, Micron unveiled the consumer-tuned C300 SSD line, based on 34 nm multi-level-cell NAND flash memories from the fab shared with partner-and-competitor Intel, last December. At the time, I urged caution, because Micron’s track record at delivering on its prior promises was hit-and-miss. And my caveat ended up, as it turns out, being justified.

Intel has had a few firmware glitches with its SSDs, leading to access lockouts, data corruption, and other problems. Whenever I’d ask Klein about his partner/competitor’s woes, I’d get a tactful response that avoided attacking Intel but instead focused on the substantial testing attention Micron devoted to its hardware and firmware development efforts. Unfortunately, that focus ended up being less than comprehensive, as early product reviewers such as AnandTech had unrecoverable issues with multiple consecutive firmware releases. Then again, Andrew ‘bunnie’ Huang had found problems with Micron’s second-generation drive (in its Crucial retail-brand flavor), too…

As of mid-May, things seem to finally be stable with the C300 series, giving Micron the green light to roll out the P300 siblings in 50, 100 and 200 GByte flavors. They’re based on single-level-cell flash memories, which provide inherently higher data integrity at a given block erase cycle count than lower cost-per-bit MLC counterparts. SLC NAND flash memory also delivers higher write speeds than MLC alternatives, whose results you may remember from my mid-November 2008 article and few-day later blog addendum. And like the C300 products, P300 SSDs harness a 6 Gbps SATA system interface, which will allow the drives’ fast read and write performance potential to shine to its fullest extent.

To wit, here’s some competitive data versus Intel and Samsung SLC-based SSDs that Micron commissioned from a benchmarking firm (which I frankly hadn’t heard of before, so take it for what it’s worth) called Calypso Systems:

Micron also uses ECC-enhanced DRAM in the P300 series, which the company claims will be priced at a competitive sub-$10 per GByte. About that system interface, however…I expressed surprise that Micron hadn’t yet equipped its ‘P’ drives with SAS capability. As I pointed out in a January 2004 feature story, for example, SCSI ‘hooks’ are deeply embedded in enterprise code, and a lack of corresponding hardware support can therefore be a deal-breaker. Klein (Vice President of Memory System Development) and the other product spokesperson on the phone, Enterprise SSD Senior Product Marketing Manager Kevin Dibelius, both strove to reassure me that plenty of IT opportunities existed for which SATA support was sufficient. And I don’t necessarily disagree with them…see, for example, my comments about WD’s 10,000 RPM ‘Raptor’ SATA HDDs (versus substantially more expensive SAS alternatives from companies like Fujitsu, Hitachi and Seagate) both in the 2004 feature article, in a follow-on mid-2007 print piece, and in my 2006 Consumer Electronics Show online coverage.

Still, Micron’s competitors are staffing up for SAS, both standalone and in partnership. Fujitsu sold its HDD business (including SAS expertise that can be applied to SSDs) to Toshiba in May 2009. Samsung and Seagate also jointly announced yesterday that the two companies were joining up for enterprise SSD controller development. And, as a Hitachi spokesperson reminded me in an email yesterday, the company has partnered with Intel for enterprise-focused reasons, as well. Near term, Micron reminded me of the availability of SATA-to-SAS bridge chips (and interposer boards based on them), which could be used to accomplish a SSD-on-SAS objective. Longer term, though, Micron may need to develop a more robust SAS approach…

…or maybe the company will choose an alternative next-generation enterprise interface path, instead. Fusion-io, as you may remember from my earlier writeup (or already know), harnesses PCI Express to link its SLC- and MLC-based flash memory boards to systems. Ironically, however, the first PCIe SSD I ever saw wasn’t from Fusion-io, it was from Micron, a prototype that the company showed at the Microsoft Windows Hardware Engineering Conference several years ago. Here’s a video, linked to a November 2008 corporate blog entry:

Klein wasn’t ready to reveal any product specifics when we talked on Tuesday. However, in a general sense he offered up the observation that Fusion-io’s strategy was silicon-light from a flash memory controller standpoint, predominantly relying on media management software running on the system processor(s). Micron’s philosophy, so it seems from Klein’s comments, will be more hardware-heavy. Both approaches have their strengths and shortcomings, and it’ll be interesting to see how the bits-vs-gates tug-of-war plays out in various market segments.