TechTarget: Russ Fellows quoted on Coho Data

“Coho Data goes all-flash with new scale-out array” by Dave Raffo

Startup Coho Data today added an all-flash version of its scale-out NAS storage system based on commodity hardware and designed for heavily virtualized VMware workloads.

The vendor also closed a $30 million funding round, bringing its total funding to $67 million.

The new DS2000f uses the same basic DataStream architecture as the DS1000h hybrid model already on the market. The difference is that the DS1000h combines PCI Express (PCIe) flash and hard disk drives (HDDs) while the all-flash DS2000f uses PCIe flash and solid-state drives (SSDs) with no spinning disk.

The independent Evaluator Group tested DS2000f performance and linear scalability by running its IOmark-VM benchmark. Evaluator Group analyst Russ Fellows said a one-node chassis achieved a 448 IOmark-VM benchmark and a two-chassis system ran up a 960 score, the highest result of any system tested. That means the one-node system could support 448 virtual application workloads (at a cost of $357.14 per VM) and the two-node system supported 960 VM workloads (for $302.08 per VM).

“The way Coho distributes and routes data is through its OpenFlow switch, which uses [software-defined networking] SDN,” Fellows said. “So unlike many of the iSCSI scale-out designs, which typically redirect I/O from one node to another, the Coho approach redirects I/O at the switch. This eliminates the back channel traffic, or intra-node I/O that creates overhead that is common with other scale-out systems.”

Fellows added that Coho Data’s scalability does have a practical limit due to the number of SDN switch ports available. Another limitation is that Coho Data only works with VMware virtual applications.