It’s quite a mouthful, but Non-Volatile Memory Express over Fabrics (NVMeoF) is shaping up to become perhaps the most disruptive data center storage technology since the introduction of solid-state drives (SSD), promising to bring new levels of performance and economy to rapidly expanding storage arrays.
NVMe over Fabrics is designed to deliver the high-speed and low-latency of NVMe SSD technology over a network fabric. There are currently three basic NVMe fabric implementations available: NVMe over Fibre Channel, NVMe over remote direct memory access, and NVMe over TCP.
When the first NVMe SSDs arrived, storage received a massive speed boost, yet the devices still talked to servers over a SCSI-based host connection, a capable yet aging technology with roots stretching back to the 1980s. “What was needed was some way to allow the NVMe protocol to be used from the CPUs on the server all the way through the network and into the storage array built with NVMe SSDs,” explains Eric Burgener, a research vice president in the infrastructure systems, platforms and technologies group at technology research firm IDC. “That’s what NVMeoF is—a way to run the NVMe protocol over a switched fabric.”
Unlike its predecessor, NVMeoF was specifically developed for use with solid-state media. “It doesn’t even work with hard disk drives (HDD), yet it gives you much better access to all the great advantages that you have with solid-state media than SCSI did,” Burgener notes.
The various NVMeoF versions offer media latency and IOPS per gigabyte that are orders of magnitude better than current solid-state-based storage systems, not to mention HDDs, observes Jeff Kimmel, storage CTO at Hewlett-Packard Enterprise. “SCSI-based SAN protocols perform very well for solid state storage, but there’s still room for improvement in both latency and resource efficiency.”
Higher throughput, lower latency
As servers grow more powerful and storage gains speed with all-flash arrays, the storage fabric will become the bottleneck preventing optimal end-to-end performance,” predicts Stuart McRae, storage director of the Lenovo Data Center Group. “NVMeoF will increase performance for both applications and the network,” he says, noting that adopters moving to NVMeoF can expect to receive a 2x improvement in throughput and 52 percebt lower latency.
NVMeoF also opens the way for the pooling and sharing of NVMe SSDs housed in external enclosures, known as JBoFs (Just a Bunch of Flashes). “By marrying external NVMe drives with a low-latency, high-efficiency fabric to access them, internal, server-attached SSDs can be replaced with shared resources,” Kimmel says.