Lowering the Cost of iSCSI SAN Boot

For more than five years, Microsoft and its hardware partners have been supporting the capability to boot a Windows Server or Windows Storage Server from a Fibre Channel—based SAN volume, and in 2005 this capability was extended to less expensive iSCSI-based SANs.

Booting from a SAN eliminates the need for hard disks on each server to hold the Windows OS and provides greater flexibility, fault tolerance, storage efficiency, and ease of backup. However, until now it required special host bus adapters (HBAs) costing US$600 or more, which can make them more expensive than the disk hardware they save.

The advent of blade servers has made OEMs particularly interested in finding a way to build lost-cost blades that don’t require a local disk drive. The lower cost of iSCSI gear, which runs over standard gigabit Ethernet, has dropped the cost of most SAN hardware, but the high cost of iSCSI HBAs remained a sticking point that has been keeping blade servers from reaching their full market potential.