To deal with data growth blowing the roof of its DAS, Detroit-based law firm Dickinson Wright PLLC decided to build...
a SAN. Sticker shock turned the company off Fibre Channel (FC) so it began examining ways to build a storage network using iSCSI connections.
After inspecting products from several SAN-in-a-box vendors, one problem surfaced immediately. The company needed technology that could support Ethernet jumbo frames capable of carrying 9,000-byte packets of information. Yet the default setting for many iSCSI SAN products is 1,500 bytes -- the standard payload of Ethernet frames since their inception in the 1980s.
Alan Hunt, operations manager at Dickinson Wright came upon iSCSI arrays by Nashua, N.H.-based EqualLogic Inc. and decided they were a good fit. First, the EqualLogic gear is designed specifically to handle jumbo frames of up to 9,000 bytes. Each EqualLogic array contains three Gigabit Ethernet (GigE) ports, allowing to stripe data across 12 active drives. The product also supports blade servers with key functions that Dickinson Wright needs, including snapshot-based backup and replication.
Dickinson Wright bought 11 PS 200 Series arrays for about $300,000 -- roughly what Hunt estimates it would have cost to construct a FC SAN. By year's end, the firm expects the arrays will supply up to 140 servers (mostly blades) with about 64 terabytes of primary storage.
For years, the firm managed well enough using Microsoft Windows servers, Windows desktop clients powered by the XP operating system, and DAS arrays. But Hunt reasoned the law of diminishing returns eventually would force the company to pay for expensive DAS much sooner -- and more often -- as its data storage needs soared.
"I still believe direct-attached storage is the most reliable technology, but it's not realistic given the size of our data storage," Hunt said. "ISCSI should enable us to give our remote locations growth capacity we couldn't provide before, at a reasonable price."
Dickinson Wright joins a growing list of companies that are gravitating to iSCSI fabric as their storage needs grow and retention periods lengthen. Enterprise Strategy Group of Milford, Mass., estimates that nearly 42% of small to midsized businesses plan to implement iSCSI SANs in 2006.
Surmounting technical obstaclesSwitching technology proved somewhat tricky. Hunt said he approached Cisco Systems Inc. about providing switches that would enable him to chain GigE ports together between servers. "But everything Cisco sent me (turned out to be) 10/100 switches for about the same price as the gigabit switches."
Instead, Hunt wound up buying 48-port network switches from Extreme Networks Inc. of Santa Clara, Calif. The hardware enables Hunt to daisy-chain 10 gigabit ports together between 1U tape autoloaders.
A secondary tier of storage is provided by the REO Series of storage appliances, produced by San Diego-based Overland Storage Inc. REO devices store data pulled from older arrays and servers, where it is then spooled from disk to tape by software from CommVault Systems Inc. of Oceanport, N.J.
Here too, jumbo frames presented a challenge. Hunt encountered compatibility problems between Overland appliances and his large-sized Ethernet packets, especially as he sought to streamline storage management at outlying offices.
"Initially I thought that everything was going to be connected directly off of the switches of the SAN fabric. But instead I ended up moving the Overland devices directly off the backup server to get it to work," Hunt said.
For now, he is forgiving of vendors, given that 9,000-byte jumbo frames are still relatively new. In the future, he said he expects more products to come equipped to interface with jumbo frames. "You have to have a lot of testing and analysis to do something that big right now."
Hunt said he expects to add at least one storage array per year for larger locations, including Detroit headquarters, a data center in nearby Bloomfield Hills, Mich., and the Washington, D.C. office. The storage of e-mail, specifically an archive for retrieving older messages that have been deleted, is on the drawing board for 2006.
Dickinson Wright is a 127-year-old law firm with five offices in Michigan and one in Washington, D.C. Literally tens of thousands of documents must be stored and readily available to the company's 210 attorneys. Costs for storing paper documents were approaching $1 million annually.
"We needed to control costs from a labor perspective. We would rather spend the money on equipment than on having people delete files to help us deal with performance issues," Hunt. said