When SSDs were first introduced to the enterprise, they were seen as lower-cost, high-I/O alternatives to short-stroked SATA and SAS drives. By adopting the same interfaces, it was easier to swap out the old drives for the new.
But now that SSDs are starting to form their own tier within high-transaction environments, the movement to establish a direct interface to the server host bus is in full swing -- the twin prizes being even greater throughput and more streamlined network infrastructure.
The default interface for SSDs (and servers, for that matter) is PCIe, but that standard is so broad that it accommodates a wide range of software drivers and other features that make integration difficult at best. But that state of affairs may be about to end as a new wave of interface formats hits the channel.
The one with the most wind behind it is Intel's Enterprise Non-Volatile Memory Host Controller Interface (NVMHCI). The company has devised a means to not only increase parallelism for memory subsystems, but has added a dose of data integrity and security. Best of all, it provides a common framework for developers to utilize the PCIe interface, avoiding SAS/SATA serializer/deserializer components and HBA controllers to gain direct access to the host bus.
The first implementation of NVMHCI can be seen next week at the Flash Memory Summit in Santa Clara, Calif. Integrated Device Technology (IDT) will show off its new flash controller and will offer a detailed session in conjunction with Intel on the interface. The standard itself is in the final stages of ratification by the NVMHCI Workgroup, led primarily by Intel, Microsoft and Dell, and is expected to be finalized by the end of the year.
Also at the summit will be OCZ to showcase its High Speed Data Link (HDSL) interface aboard the new 3.5-inch IBIS drive. The combo provides a transfer speed of 2.5 GBps and is designed to outfit enterprise SSD tiers with high-bandwidth operation by avoiding the slower SATA infrastructure.
High throughput on the SSD itself has served the Flash memory industry very well up to now. When the major markets were laptops and mobile consumer devices, there was no real need to worry about networking. That simply won't do in the enterprise, however. Here, the SSD is part of a team, and the easier it is to integrate with other players, the more effective it will be.