New kid on the storage block
- By John Moore
- Jul 19, 2004
This could be the year that iSCSI debuts on your network.
Internet SCSI — better known as iSCSI — emerged as a draft standard in 2002 and received the full blessing of the Internet Engineering Task Force early last year. But the technology appears to be hitting its stride now, as support for it grows among storage vendors.
The key appeal of iSCSI is that it delivers block-level storage via a standard IP network, an infrastructure that is already in place at most organizations. Network-attached storage also uses IP networks, but does so to transfer file-level storage.
The lower block-level access is important for databases and other applications that benefit from the higher performance.
Until now, information technology managers who are moving away from the traditional but constrictive storage model — where storage attaches directly to servers — had one main alternative for handling block storage: Fibre Channel-based storage-area networks (SANs).
That approach, although effective, has proven too expensive for some storage customers. Fibre Channel SANs represent another network that must be maintained in addition to an organization's primary data pathway — typically Ethernet networks based on TCP/IP.
"Most of our customers have been trying to step away from direct-attached storage for quite some time," said Dan Smith, enterprise technology consultant with GTSI Corp.'s storage technology team. "The main problem is being able to deliver block-
level storage at prices that are lower than the Fibre Channel alternative."
iSCSI promises to do just that. The main cost savings comes from the ability to use existing networks and not having to invest in Fibre Channel gear and support specialists. "You don't have to build a Fibre Channel infrastructure," said John DeNardo, IT director for Eagle County, Colo. "As a result of that, your costs go down."
County officials have installed an IP-based SAN using LeftHand Networks Inc. products. DeNardo said the IP SAN's purchase price was two to three times less than a Fibre Channel SAN. The IP SAN also helps the county government save on training. "I would consume my annual training budget to train one guy to do Fibre Channel," he said.
Lower operational costs make IP SANs attractive to resource-constrained government agencies, industry officials said.
When it comes to iSCSI deployment, customers can opt for what George Crump, vice president of technology solutions at storage integrator Sanz Inc., describes as a turnkey solution. Vendors such as Equallogic Inc. and LeftHand Networks offer iSCSI packages that include disk arrays and SAN management capabilities. Turnkey IP SANs of this type generally cost $15,000 to $25,000, according to industry watchers.
In other words, a managed IP SAN costs less than $10 per gigabyte, said Tom Major, vice president of marketing at LeftHand Networks. A managed Fibre Channel SAN, he added, may cost $40 to $50 per gigabyte.
An iSCSI SAN may become the storage network of choice for officials at small to midsize organizations who find Fibre Channel too expensive. But larger organizations with existing Fibre Channel networks can also take advantage of iSCSI. A device called a storage router can be installed to translate between iSCSI and Fibre Channel. The router intermediary lets servers on an IP network access Fibre Channel storage.
"The router type of solution will be for the more traditional data centers where they have an existing SAN and want to extend its use for more servers," Crump said. Storage routers of this type start at about $12,000.
Moore is a freelance writer based in Syracuse, N.Y.