By Dave Simpson
Last week, Microsoft announced the availability of its iSCSI software initiator package, which includes a software driver and initiator service. The software works with Windows 2000 client and server versions, Windows XP, and Windows Server 2003 and is available for free download at www.microsoft.com/downloads.
Ratified as a standard by the Internet Engineering Task Force (IETF) earlier this year, iSCSI enables block-level storage traffic over IP networks.
Analysts say that the free driver and Microsoft's strong support for iSCSI may give the storage area network (SAN) protocol the shot in the arm that it's been lacking since development began three years ago. (Cisco and IBM submitted an iSCSI draft specification to the IETF in 2000.)
In an analysis of Microsoft's iSCSI strategy (which will be published in the August issue of InfoStor), John Webster, founder and senior analyst at the Data Mobility Group, writes: "Microsoft is breaking down the barriers to iSCSI adoption...because iSCSI solves problems for Microsoft, particularly those related to Exchange. We believe Microsoft can single-handedly create the big iSCSI boom that eluded Cisco and IBM."
The problems that Webster alludes to have to do with the fact that direct-attached storage limits the growth of Exchange databases. In addition, Webster argues that Microsoft "has never been comfortable with the network-attached storage [NAS] alternative," and that the other alternative--Fibre Channel SANs--is too complex and costly for Microsoft's mass-market strategy.
The Public Broadcasting Service (PBS) is one of the early users of a beta version of Microsoft's iSCSI drivers. PBS built an IP SAN based on Microsoft's drivers and StoneFly Networks' iSCSI-based i1500FS Storage Concentrators in order to link "stranded servers" to a Fibre Channel SAN. PBS's dual SANs also include IBM's "Shark" and FASt T500 disk arrays, and standard Gigabit Ethernet network interface cards (NICs) from Intel on the hosts in the IP SAN. In addition to routing, StoneFly's Storage Concentrator software provides storage provisioning, virtualization, and IP SAN management capabilities.
According to Ken Walters, senior director of enterprise platforms at PBS, the key goals behind implementing the IP SAN were reduced costs and improved data availability.
"iSCSI solved the 'stranded servers' dilemma we faced by making it cost-effective to hook up tier 2, tier 3, and development servers to a SAN," Walters explains, adding that the company is pursuing a "peaceful co-existence" strategy with its IP and Fibre Channel SANs. Walters says that PBS did not encounter any integration or interoperability problems with the iSCSI implementation.
PBS connected the "stranded servers" to the Fibre Channel SAN via iSCSI because direct Fibre Channel attachment would have been too expensive, according to Walters.
Microsoft's iSCSI initiator package includes support for data encryption--including Internet Protocol Security (IPSec)--Internet Storage Name Service (iSNS) for clients and servers, management via Windows Management Instrumentation (WMI), and an architecture that aggregates different hardware initiators into a common framework.
Microsoft claims that more than 85 vendors are developing Windows-based applications and storage hardware for iSCSI. The company has created an iSCSI Designed for Windows Logo Program to enable hardware vendors to qualify their products with Windows platforms.
A more detailed article on iSCSI, Microsoft's drivers, and the PBS IP SAN will appear in the August issue ofInfoStor.