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While being all-NVMe brings performance advantages over SCSI-based protocols used in existing flash media, such as SAS and SATA, the data path end-to-end in FlashArray//X will not yet realise the full potential of NVMe.
Pure has chosen to make NVMe the back end connect from controller to drives but connectivity to hosts is Fibre Channel and iSCSI. The controller performs fundamental functions such as protocol handling and physical addressing, as well as storage services such as data reduction, replication and encryption that Pure believes are important to its customers.
That means the controller will still act as a bottleneck to some extent, though Pure expects to offer NVMf (NVMe over fabrics) this summer in a move that will almost completely free up the potential performance gains of NVMe.
Pure Storage CTO of Europe, the Middle East and Africa, Alex McMullan, said: “What we’ve done is move the drives out of the way and made software the problem. But with FlashArray//X I’ve seen latency of 200μs, which is half the latency of our other systems.”
McMullan said Pure plans to make the FlashArray//X NVMf connected later this year. It will be demoed at its user event in June. NVMf connectivity could help to remove the bottleneck at the controller and allow NVMe to be the transport from media to host.
The FlashArray//X is based around Pure’s own proprietary NVMe-based DirectFlash hardware modules that come in 2.2TB, 9.1TB, and 18.3 TB raw capacities.
Pure says using the 18.3TB capacity module will allow FlashArray//X to deliver more than 1PB of raw storage from a 3U base chassis that translates to a claimed 15PB after data reduction.
On the software side a new DirectFlash software module in the Purity operating environment puts flash management functions such as garbage collection, allocation, I/O optimisation, error correction into the (also new) //X70 controller.
Read more about NVMe/NVMf
- NVMe brings blistering performance gains over existing HDD-era disk protocols, and is a straight swap-in for PCIe server-side flash with array and hyper-converged products on the way.
- NVMe over fabrics takes the built-for-flash advantages of the PCIe-based protocol, and allows NVMe to be sent via Fibre Channel, Ethernet and Infiniband networks.
NVMe is a PCIe-based standard that potentially allows flash storage to break through the limits imposed by SCSI and its use in the disk-era SAS and SATA protocols by providing a vast increase in the number of queues and possible queue depth over those standards.
FlashArray//X with 2.2TB and 9.1TB DirectFlash Modules will ship as a directed availability release in Q2 2018. General availability of FlashArray//X, which will support 18.3TB DirectFlash Modules and upgrades from existing FlashArray//M systems, is expected in the second half of 2018.