SAN JOSE, Calif. – A wide group of vendors is poised to roll solid-state drives for the PCI Express bus, promising improved performance over current flash drives that mainly use serial ATA and Serial-Attached SCSI interfaces. The wave of new products will continue the current split between SATA- and SCSI-based protocols, and accelerate the shift to competition based on new software features.
As many as 80 companies including Dell, Intel, Micron, Oracle and Stec are part of the trade group that defined the NVMe interface last year. The first drives using the interface are expected to ship later this year.
Separately, the SCSI Trade Association (STA) recently announced it will adopt the SCSI over PCI Express standard being completed by the ANSI T10 committee. STA will hold a technology showcase in Silicon Valley on May 9 where members may demo some of the first SCSI Express flash drives.
The competing NVMe and SCSI Express drives are expected to continue the same split between SATA and SCSI command sets that exists in today’s SATA and SAS flash and hard-disk drives.
The NVMe and SCSI Express drives represent a challenge to Fusion-IO, a startup that soared to success based on pioneering the move to plugging solid-state drives into the fast PCIe bus, closely linked to system CPUs. Most first-generation solid-state drives used the slower SATA and SAS hard drive interfaces that reside lower in the hierarchy of interconnects on a server.
The performance benefits of PCIe helped Fusion IO tap into sales that soared to $84 million in its most recent quarter. The strong sales supported two successful public offerings in the past two years, raising more than $300 million.
With the advent of many more PCIe flash drives this year, Fusion faces a two-fold challenge. A wider supply of standard drives could help speed price decreases in the sector. In addition, the presence of more solid-state drives will likely narrow Fusion’s performance benefits based on its proprietary approach.
Fusion pioneered a method of giving host CPUs fast access memory stored on flash drives. The company has a proprietary approach for sharing with the host processors a map that describes where all the data on a flash drive physically resides, enabling write access at latencies of as little as 15 microseconds. Most drives maintain less comprehensive logical-to-physical translation maps on the drive controllers and thus have higher latencies.
The new NVMe and SCSI Express specs will enable vendors to leverage common software stacks for PCIe drives, lowering their costs and time-to-market.
“Today most PCIe flash drives include a proprietary driver and no industry software standard,” said Amber Huffman, a spokeswoman for the NVMe group and a senior principal storage engineer at Intel. With NVMe’s consistent feature set, “we expect to see faster time-to-market and broader adoption,” she said.
For its part, Fusion will back the SCSI Express approach because it is based on the work of a recognized standards group, the ANSI T10 committee. Access to the NVMe spec requires signing a legal document managed by Intel Corp., the group’s leader, said Gary Orenstein, vice president of products at Fusion IO.
“Is too early to tell what the shift to NVMe and SCSI Express will mean,” said Orenstein. “Some people think there could be a merging of the two efforts eventually,” he added.
To date, nearly three-quarters of Fusion’s sales have gone to three large customers, likely the top server makers—Dell, Hewlett-Packard and IBM. Dell has already signaled its support for NVMe in its latest servers, casting a shadow over at least one of Fusion’s big customers.
As part of the SNIA Solid State Storage Initiative, the PCIe SSD Taskforce is taking an SSD-oriented approach, and isn't promoting a particular interface or technology. We are aiming to educate the market about PCIe SSDs and fill any holes where current standards may be lacking.
As an old fart, this has some appeal to me... but exactly which bus would you choose? (I remember that problem too).
PCIe is really quite elegant, fast and supported by most architectures including some ARMs and a few FPGAs.
Apart from maybe running code directly out of flash, what application would benefit from a direct mapped approach versus smart intermediate controller than can take care of bad blocks, wear levelling etc?
You might have missed that HP and Fusion-io are key promoters of the SCSI Express standard. In fact, HP demonstrated upcoming SCSI Express products with Fusion-io last November at HP Discover in Vienna.
Connecting Directly to the System Data and Address Bus is the best and Fasted way of Connecting the Memories with the Host CPU. PCIe is still an intermediate way of doing it.
If Intel, Microsoft, Apple and AMD come together and work of the interface standard for directly connecting the Flash/SS Drives with System Data and Address Bus then it will really change the way computing systems works today.
The latency in the HDD access was hiding the latency of the interfaces like ATA, SATA and SCSI interfaces but that is not true in case of Solid State Memories.
Good article, but it missed a new activity sponsored by the SNIA Solid State Storage Initiative - the PCIe SSD Taskforce - that has its first meeting on April 9. Take a look at www.snia.org/forums/sssi/pcie.
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