Verari's SB5165XL StorageServer blade holds up to 12 TB in a 1U vertical device. The networked appliance connects two blades to a storage controller, for a total of 24 TB. The blades are built to fit into Verari's BladeRack2 chassis, which holds up to 72 slots. A fully populated chassis of storage blades will hold up to 24 controllers and 48 storage blades, for up to 576 TB in one chassis. The blades can connect to Verari's server blades through iSCSI, CIFS or NFS protocols.
While customers can connect any server in the chassis to any of the storage blades, and multiple servers can share the storage blades, the storage capacity within the chassis doesn't include a virtualization layer to pool the storage. VMware's VMFS, which enables VMotion and other third-party storage virtualization software, can provide virtualization. Eric Seidman, manager of storage systems for Verari, said that the company wants to add its own virtualization to its blades. "We're definitely looking to add this type of technology, and it's possible with our architecture," he said. "This announcement is an evolutionary step."
Storage blades must also overcome the same concerns that users had about blade servers. Concerns about cooling the densely packed chassis hampered adoption of blade servers early on, although one analyst said that is no longer the case. "That's old news now," said Jim Burton with Ideas International. "Blade servers are now a couple of generations in, and processors have come down in size and generate much less heat."
Concerns about blade systems may be waning, but they have not disappeared. In TechTarget's 2007 Server Decisions Survey, nearly 30% of 218 respondents said that cooling concerns were enough to preclude their organization from investing in blade servers. About 27% of the respondents cited the cost of the chassis as a concern, and 21% cited vendor lock-in with proprietary chassis.
Seidman said that adding spinning drives shouldn't add much heat because each drive only generates about 8W of heat, compared with 80W to 90W for processors. The Verari chassis have a 0.375-inch space between each hardware component and a three-level vertical cooling system built in. "We're able to cool about 30 kW within the rack," he said.
Shock and vibration are also a concern with blades. Verari has attempted to mitigate this through a proprietary installation assembly for the hard drives on the blade's aluminum heat sink, as well as through testing with disk drive supplier Western Digital.
The SB5165XL StorageServer blade appliance, consisting of two storage blades and one storage controller, is available for $36,000. The BladeRack 2 chassis starts at $17,692.