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Datrium DVX server-side flash storage comes out of stealth

Datrium built its DVX software and NetShelf system for customers that want to use low-cost flash in servers to separately scale performance and capacity.

Storage startup Datrium Inc. today emerged from stealth with a product that puts a local twist on server-side flash storage management.

The Datrium DVX Server Flash Storage System consists of Datrium DVX server-side flash management software and a 2U NetShelf appliance for back-end storage. Unlike other server-based flash approaches, Datrium does not use host flash for persistent storage.

DVX software runs at the vSphere hypervisor level, and consolidates RAID protection and data reduction on individual VMware ESXi hosts. Local solid-state drives (SSDs) are used only to cache reads. Sequential writes are sent to near-line Serial-Attached SCSI (SAS) disks in NetShelf for high availability and shared storage. DVX software talks to NetShelf via a 10 Gb Ethernet connection.

The Datrium platform lets users assign storage performance and protection policies to discrete hosts, similar to how virtual machines (VMs) are managed.  

Datrium bills its storage system as a "bring your own flash" model that works on commodity servers and supports generally available flash drives, including consumer-grade SSDs. Customers scale performance and capacity independently by adding flash storage to servers or additional physical hosts.

"We kind of split the model that most people planned on using for flash," said Datrium CEO Brian Biles. "Instead of flash being scarce and expensive, we make it [so] flash is abundant and cheap."

Datrium DVX Server Flash Storage is in limited availability now. The vendor said pricing and benchmark test data would be available when the product is generally available later in 2015.

Although a startup, Biles and other Datrium executives are recognizable names in the storage industry, with roots in Data Domain Inc. and VMware. Biles founded Data Domain and joined EMC as a vice president of product management when EMC acquired the Data Domain line of backup and deduplication disk appliances in 2009.

Datrium CTO Hugo Patterson was chief architect at Data Domain and a CTO of EMC's Backup Recovery Systems Division. Also on board at Datrium are top ex-VMware engineers Boris Weissman, Ganesh Venkitachalam and Sazzala Reddy. Former Data Domain CEO and current ServiceNow Inc. CEO Frank Slootman, and VMware founders Diane Greene and Mendel Rosenblum are investors.

Reflecting the founders' backgrounds, Datrium blends elements of storage virtualization, flash and disk-based storage geared to heavily virtualized VMware shops. But the startup doesn't fit neatly in a typical storage classification, Biles said.

"Datrium is a new approach to how storage is considered, even categorically," he said. "It's not an array because all the RAID and data services are computed on the host. We're not hyper-converged storage because we don't sell servers. And we're definitely not software-defined storage, since we include a rack-mounted appliance."

Steve Duplessie, a senior analyst at Enterprise Strategy Group Inc., based in Milford, Mass., said Datrium builds on an industry-wide push to get flash storage closer to host servers.

"The theory is a pretty good one," Duplessie said. 'By putting all of the heavy storage-centric functions in the server cores themselves, you completely eliminate the storage controller bottleneck. Every server is essentially also its own storage controller, so it never competes with others for resources. It's hard to do, but these guys have a history of doing hard things."

DVX software runs on server hosts rather than in a system's operating system software kernel. Instead of pooling writes across node clusters, each host's I/O is separated from other hosts. NetShelf acknowledges when host-based writes are made to battery-backed, nonvolatile random access memory. If the system detects frequent cache misses on a VM workload, DVX software recovers the data from the host flash.

Datrium's inaugural release is limited to a single NetShelf chassis, with 12 drive slots for 4 TB SAS disks and 48 TB or raw storage. About 30 TB is usable after RAID calculations. Effective capacity ranges from 100 TB to 120 TB with Datrium's inline data reduction. 

Biles said pricing will be based on the available capacity per each NetShelf. The DVX software license supports an unlimited number of server hosts and flash capacity.

By design, Datrium does not support on-host copies or host-to-host write replication. Replication, inline deduplication and compression, and copy-on-write snapshot clones occur per virtual disk.

"We let you manage storage like you manage VMs. There are no storage artifacts like LUNs, zones or aggregates -- just VM admin extensions," Biles said.

Beta customer Northrim Bank in Anchorage, Alaska, has been running a Datrium beta system with a 1 TB flash drive purchased off Amazon for $400, according to Northrim CIO Benjamin Craig. He said he has used the system mostly in test and development, but has placed some production on it after putting it through early paces.

Craig said Datrium DVX answers his "Christmas list" of desired features for simplified storage management.

"We replicate our most sensitive, mission-critical servers between our primary and secondary data center every five minutes," Craig said. "For our mail server, it's every hour. Because those individual settings for replication and protection happen at the volume level, we had to break up our VMs into volumes, which creates volumes of space that became unusable to us. With Datrium, I can granularly set specific performance and protection schedules to each VM out of a single data store. I'm no longer limited to [setting it] at the volume level."

Craig said the most likely use case for Datrium after it becomes generally available is to run virtual desktop infrastructure. He said he expects to add flash and also use it for primary data after retiring an aging Dell EqualLogic SAN. Northrim also uses Nimble Storage arrays.

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