Section 3.6. Windows and NAS

   

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3.6 Windows and NAS

Microsoft offers a commercial package often referred to as the Server Appliance Kit (SAK) for the benefit of original equipment manufacturers (OEMs) wishing to develop a network-attached storage appliance. The SAK is simply a version of Windows in a modular form, along with some development tools. The modular form of Windows allows an OEM to pick and choose (within reason) the Windows components that it wishes to include with its offering. The idea is to pare down Windows to the bare bones required for running the network protocol stack, a file server, and a local storage stack. The development tools allow OEMs to develop some quick administration tools and brand their offerings.

The SAK also has some components that are not part of the regular Windows server offerings. A good example is the reliability framework that monitors drivers for memory leaks and silently restarts critical components as needed. Several vendors offer NAS devices that use Windows NT as their operating system. One advantage of using Windows within NAS devices is the reduction in cost and time to develop such an offering. The CIFS and NFS protocol stacks are readily available from Microsoft. Probably the biggest advantage is that one gets all the new SMB enhancements that Microsoft builds without having to do any major development and reverse engineering.

Another advantage is that the Microsoft Server Appliance Kit provides for a quick and easy way to build customization into the offering. The SAK includes some management features (e.g., remote management features) and data protection features (such as a snapshot capability). (See Chapter 5 for an explanation of snapshot technology and its uses.)

On the other hand, some OEMs have developed their NAS offerings without using the SAK. Some CIFS and NFS stacks are freely available. The open -source phenomenon does have its appeal , and if one is willing to spend the resources, the advantages of working with source code that one can modify also has its benefits, such as ensuring that the operating system layer is as thin and efficient as possible. A market study of the two approaches is beyond the scope of this discussion.

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