Windows NT May Appear to Hang When a Mirrored IDE Drive Fails.

 Last reviewed: October 1, 1997
Article ID: Q172912
The information in this article applies to: 

  - Microsoft Windows NT Server versions 3.5, 3.51, and 4.0

SYMPTOMS

When you perform Windows NT mirroring on a computer using IDE drives and the master drive on the Primary channel fails, the system may appear to stop responding. You may also experience very erratic mouse movement. This can happen even if the system drive is configured as master on the primary EIDE controller and shadow drive is configured as master on the secondary EIDE controller.

CAUSE

When your computer is running Windows NT, the ATAPI device driver continues to request communication to the primary EIDE device on the master channel. This process will eventually timeout and Windows NT will then continue to run by using the primary (shadow) drive on the secondary channel. The length of this timeout delay depends on the processes running and the specific hardware in use.

RESOLUTION

Because of the nature of IDE architecture, the system may appear to stop responding or erratic mouse movement may occur. This behavior is expected when a mirrored IDE drive fails.

If an instantaneous switchover from the primary drive to the shadow drive of the mirror set is desired, then switching to a SCSI-based disk subsystem is recommended.

MORE INFORMATION

When the original system or boot drive fails, you will have to use a Windows NT boot floppy disk to start from the shadow partition or reconfigure the shadow disk drive as the master disk drive on the primary controller.

If the drives are not the same geometry, then you may still not be able to boot off the shadow drive even when moved to the primary drive's position on the IDE channel.

For additional information, please see the following articles with related topics in the Microsoft Knowledge Base: 

   ARTICLE-ID: Q141702
   TITLED    : How to Recover Mirroring Windows NT Using IDE devices

   ARTICLE-ID: Q119467
   TITLED    : Creating a Boot Disk for an NTFS or FAT Partition

   ARTICLE-ID: Q114779
   TITLED    : Overview of Disk Mirroring (RAID Level 1) in Windows NT

   ARTICLE-ID: Q128630
   TITLED    : How to Recover From a STOP 0x00000058 FTDISK_INTERNAL_ERROR
NOTE: Software mirroring with Windows NT does NOT mirror Master Boot Record/Partition Table entries. This is because software mirroring is only designed to mirror a partition's data, and cannot guarantee boot capability of the Shadow (mirrored) drive. Thus, you should always have a valid Windows NT Fault Tolerant boot floppy disk created in the event the Primary drive fails.

Fault Tolerance is not a replacement for regular backups. 

Keywords          : ntfault nthw NTSrv kbhw
Version           : WinNT:3.5,3.51,4.0
Platform          : winnt

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Last reviewed: October 1, 1997
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