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Comment by bitL | Hacker News Reader

What would be the advantage of this comparing to PCIe/M.2 PCIe SSDs? Is it all about reduced latency, i.e. very small reads/writes would benefit?

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>The benefit of using a DDR3 interface instead of SATA/SAS or PCIe is lower latency because the SSDs sit closer to the CPU. The memory interface has also been designed with parallelism in mind and can thus take greater advantage of multiple drives without sacrificing performance or latency. SanDisk claims write latency of less then five microseconds, which is lower than what even PCIe SSDs offer (e.g. Intel SSD DC P3700 is rated at 20µs).

Source: http://www.anandtech.com/show/8396/fms-2014-sandisk-ulltradi...

TL;DR about 4x faster then PCIe SSD's

Although it is apparently implemented via Sata on the module so there is scope to speed it up more.

But raw flash writes on the order of 1-2 milliseconds, so the 5 microseconds must be the latency to write to a ram cache inside the stick. I wonder what the latency would be for a write larger than the buffer. For that matter, how large is the buffer?

If you read the source you will see that no independent benchmarks have been done yet.

The article did update with a benchmark link comparing a couple of models to a fusion io card.

http://www.percona.com/blog/2014/08/12/benchmarking-exflash-...

So the 95%, write latency is 1-1.5 msec for one model, and 2.5-3.5 msec for another model. Maybe representing SLC/MLC flash?

95% read latencies are maybe 350 or 250 usec.

see http://www.percona.com/blog/2014/08/12/benchmarking-exflash-... for benchmarks of the IBM version of it against FusionIO PCIe

One big benefit is that it provides a way to add flash to systems with no PCIe slots, like blade servers.

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