More than 20 storage vendors were in Redmond, WA, this week at the Microsoft Virtual Disk Service (VDS) 1.1 plugfest. VDS 1.0 was first introduced along with Windows Server 2003, and 1.1 is now in beta with general availability expected by year-end.

VDS provides the ability to virtualize hardware in a SAN at the spindle level to management applications. It has an open API for software providers. VDS 1.0 supported Fibre Channel only, while 1.1 supports iSCSI and multi-pathing management.

Claude Lorenson, group product manager for storage technology in Microsoft’s Windows Server Division, says that vendors will be able to earn the “Designed for Windows” logo, which will be important for the new Windows Server 2003 R2 feature, Storage Manager for SANs.

“Storage Manager for SANs is a management application to provision LUNs from Windows servers, no matter what type of back-end storage is on the SAN,” says Lorenson. “All of our partners will want to be VDS partners so that their storage arrays can be provisioned directly from Storage Manager for SANs.”

To bring more richness to the provisioning of the storage management application, vendors such as Brocade, Computer Associates, Emulex, and QLogic are writing VDS management applications for features such as switch virtualization and host bus adapter (HBA) management. Lorenson says that the tools Microsoft is providing in VDS do not provide those features. However, VDS does create, extend, delete, and monitor the health of LUNs from a Windows-based management tool.

It is necessary for iSCSI storage providers to be VDS providers in order to be compatible with Microsoft’s Simple SAN program.

“The big driver for the storage vendors is ease of use and simplicity,” says Lorenson. “SANs are typically viewed as complicated and difficult to support, so making things simpler in terms of management and deployment for Windows administrators, as opposed to a storage experts, is very important.”

Other key features and functions of VDS include:

  • A management protocol that allows administrators to extend or delete LUNs in storage arrays at the hardware level;
  • The ability to monitor the health of LUNs in case data corruption starts to occur;
  • A protocol that exposes the inner working of storage arrays to the operating system; and
  • The capability to provision a SAN regardless of which vendor’s product is on the back-end, providing users with more freedom in terms of the vendors they choose.


Vendors attending the VDS plugfest included Accusys, Adaptec, Brocade, Computer Associates, EMC, Emulex, Engenio, EqualLogic, Hewlett-Packard, Hitachi, Infortrend, Intransa, iStor Networks, LeftHand Networks, McData, NEC, Network Appliance, Promise Technology, QLogic, StringBean Software, Symantec, and Xiotech.