A fault tolerant disk technology supported by Microsoft Windows NT Server. Disk duplexing is essentially the same as disk mirroring, except that a separate disk drive controller is used for each mirrored drive to provide additional fault tolerance.
This provides two levels of fault tolerance:
You can establish disk duplexing on Windows NT systems at the partition level. In terms of system recovery and management, there is no difference between disk mirroring and disk duplexing.