Zen Internet provides a range of Internet and IT services to approximately 90,000 consumer and business customers...
from its main data centre running VMware ESX virtual servers in Rochdale, Lancashire, as well as secondary sites in Manchester and London.
The company originally moved to shared SAN storage when it began to offer email and Web domain hosting. Its first SAN was a Xyratex iSCSI product, which caused Zen Internet to look at upgrading to a Fibre Channel setup, said senior systems designer Graeme Hinchliffe.
"It wasn't up to scratch," Hinchliffe said. "We struggled to get more than 150 MBps throughput because it was SATA based and the cache was small. Also, we had support quirks that were never resolved, such as the controller losing the ability to be managed and RAID 5 performing abysmally."
It was after running up against these limitations that Hinchliffe's team considered the options available on the market and short-listed products from five SAN vendors: Dell EqualLogic, EMC, Hitachi Data Systems, NetApp and Sun Microsystems (now owned by Oracle).
Following the evaluation period, Zen Internet opted for three Hitachi AMS 2300 SANs and one AMS 2100. Two of the AMS 2300s support services such as hosted email, Web and backup, while the other supports circa 170 VMware servers. The AMS 2100 is used for backup and disaster recovery (DR) at the company's second site in Rochdale to which data is replicated using Hitachi TrueCopy Synchronous.
Drive types are 2:1 SAS to SATA with tiered storage putting high-performance applications on the former and less performance-critical data such as backups residing on the SATA drives.
Hitachi AMS SAN subsystems ultimately won out over EMC's Clariion -- which Hinchliffe rejected in a final run-off with Hitachi -- because of its back-end Fibre Channel Arbitrated Loop (FC-AL) drive connections. "It seemed dated and HDS had SAS connections," he said. NetApp filers were also rejected on technical grounds. "We needed block access, and it felt like NetApp was putting block I/O on top of its WAFL file system," Hinchliffe said. Dell EqualLogic was rejected because of Zen's previous poor experience with iSCSI access, while Oracle-Sun Microsystems was rejected early in the process based on cost.
For Zen Internet, the key benefit of the HDS SAN over its previous Xyratex implementation is the speed of throughput, Hinchliffe said. "We did a comparison of server I/O queue times and with the HDS SAN it was a factor of 10 or 20 times better than with Xyratex. It's also more flexible and we can supply RAID groups and partitions for specific services," he said. The support and management overhead is also much reduced for Hinchliffe's team, and future scalability is a simple process.
Where could Hitachi do better? "Our main gripe is that the user interface is not easy to use, but I believe HDS is addressing that in September," Hinchliffe said.