If clustered NAS is the way to go, why do traditional NAS systems still account for the majority of deployments?
For many CIOs, the limitations of conventional NAS systems are a nonissue because their applications fall well below those thresholds. Other factors are more important, including ease-of-use and the ability to consolidate data from multiple applications into a single repository -- and not necessarily a single file system.
Cost is also an important aspect. "What drives most of these decisions nowadays is the financial aspect," says Glen Duzy Sr., a consultant at GlassHouse Technologies. "The desire to save money can bring [customers] toward the appliance model. Most of the commercial accounts are more concerned about the operational cost and the availability."
An interesting example of how adopting a traditional SAN plus NAS can save the day comes from Jerome Waldron, CIO of Salisbury University in Salisbury, Md. SU is a midsize university, Waldron explains, lacking perhaps the financial and technical resources of larger institutions, but with an equally sophisticated set of requirements to serve its personnel and 7,000 students.
SU's IT department was facing some serious challenges, including migrating from old applications to PeopleSoft, managing an exploding volume of e-mail messages, and managing daily tape backups.
"We had to move away from tape," Waldron says, explaining that there weren't enough hours in a day to perform tape backups for the university's roughly 100 servers.
Storage was a key factor because the data from the various SU applications was dispersed across old and incompatible storage devices, including obsolete Novell NetWare servers and an imaging solution that was no longer supported by Minolta, but which hosted about 1 million digital images.
SU's solution was to install an EMC Clariion 600 with two tiers of storage, including 4TB of Fibre Channel drives for the most demanding applications and 16TB of ATA drives for archiving and backups. The university also deployed an EMC Celerra gateway to support its file-serving needs.
The new storage system has made it possible to consolidate all of the university's applications and move to daily, unattended, disk-to-disk backups. Using the Celerra NAS also made it possible to reduce the number of servers by 25 percent, with obvious savings on equipment purchase and maintenance.
Might a clustered NAS solution have better served the University's needs? Quite possibly not. SU did not have two typical requirements that always raise the clustered NAS red flag: leading file-transfer performance and a single namespace in the hundreds of terabytes or larger. What's more, a clustered solution would have lacked some capabilities, such as simultaneous SAN and NAS access to the same box.