Windows NT-based disk striping and disk striping with parity implement RAID features in software, using any vendor's hardware that is compatible with the operating system. Because these are software-based solutions provided with the operating system, they offer a cost advantage.
Disk striping writes data in stripes across a volume that has been created from areas of free space. These areas are all the same size and spread over an array of disks (up to 32). Striping writes files across all disks, so data is added to all partitions in the set at the same rate.
Windows NT-based disk striping implements RAID level 0. Disk striping provides the best performance of all Windows NT Server disk management strategies but does not provide fault-tolerance protection.
Disk striping with parity is similar to disk striping. It adds a parity-information stripe to each disk partition in the volume. This provides fault-tolerance protection equivalent to that of disk mirroring but requires much less space for the redundant data. Windows NT-based disk striping with parity implements RAID level 5.
When a member of a stripe set with parity fails in a severe manner¾such as loss of power or a complete head crash¾you can regenerate the data for that member of the stripe set from the remaining members.
Stripe sets with parity are a good solution for data redundancy in a computing environment in which most activity consists of reading data. Stripe sets with parity also improve write performance, but not as much as with striping alone. Creating a stripe set with parity requires at least three physical disks on the server.
Disk striping is available on both Windows NT Server and Windows NT Workstation. However, disk striping with parity is supported only for Windows NT Server (it is not supported for Windows NT Workstation). On a dual-boot computer, stripe sets, including those with parity, are not accessible when running the MS-DOS operating system.
Disk striping with parity provides a performance improvement for the reading of data compared to a single device or a mirrored device. Striping with parity is recommended over mirroring for applications that require redundancy and are read-oriented. However, the use of striping with parity requires more system memory than using mirroring. Also, when a member stripe is missing, it loses its performance advantage.
Disk striping and striping with parity are set up and managed using the Microsoft Windows NT Disk Administrator program that can be started from the Administrative Tools program group. For information on setting up disk striping or disk striping with parity, see your documentation for Windows NT Server or the online Help for Disk Administrator. Also see the Windows NT Resource Kit.