Windows 2000 Performance Guide

RAID and Windows 2000

Now that we have discussed the various RAID levels in general, let’s get specific and see what high-availability disk options are available on a Windows 2000 machine. We need to consider two types of solutions: hardware RAID implementations and software RAID implementations. The main difference between the two is how the request to a logical device is decomposed into subrequests to physical devices. Windows 2000 software RAID support is extensive, the most extensive built into any operating system we know. But it cannot offer automatic data recovery like hardware RAID can. There is a wide selection of hardware RAID options available, ranging from controller cards to separate RAID enclosures from many different manufacturers. Because new RAID disk products are emerging constantly, only a general account of the configuration issues is possible. Where appropriate, we refer in detail to specific vendor products to illustrate the major points of the discussion.

Hardware RAID

In general, the better hardware RAID solutions supply virtually continuous data availability, making worrying about outages due to disk failures a thing of the past. (Unfortunately, hardware disk failures cause a disappointingly small fraction of the “unplanned” system outages that occur.) Fault tolerance of a hardware RAID configuration is enhanced when the disks themselves are connected across multiple controller interfaces, and there is failover driver software to allow one controller to ...