DOCUMENT:Q316311  10-APR-2002  [winnt]
TITLE   :HOW TO: Configure a Mirror Set on Windows NT Server 4.0
PRODUCT :Microsoft Windows NT
PROD/VER::4.0
OPER/SYS:
KEYWORDS:kbenv kbhw kbtool kbAudITPro kbHOWTOmaster

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The information in this article applies to:

 - Microsoft Windows NT Server version 4.0 
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IN THIS TASK
------------

 - SUMMARY

    - Requirements
 - Configuring a Mirror Set on a Windows NT Server 4.0 Computer

 - REFERENCES

SUMMARY
=======

This step-by-step article describes how to configure a mirror set on a Windows
NT Server 4.0 computer. A mirror set is a set of two equal-sized partitions that
are exact duplicates of each other, and which are located on two separate
physical disks. When data is written to the mirror set, it is written to both
partitions. Mirror sets can be very useful because provide a very high level of
fault tolerance.

Requirements
------------

 - A computer (that meets the requirements listed on the Hardware Compatibility
   List) on which Windows NT Server 4.0 is installed.
 - One blank hard disk, that is at least as large as the partition you want to
   mirror, must be installed in the computer. If you are configuring a mirror
   set of the boot partition, the disk should be identical (same manufacturer,
   model number, and size) to the disk that contains the boot partition.

Configuring a Mirror Set on a Windows NT Server 4.0 Computer
------------------------------------------------------------

You can use Disk Administrator to configure a mirror set on a Windows NT Server
4.0-based computer. Any partition can be mirrored to another disk of equal or
larger size. You must be logged on as an administrator, or as a user that has
administrator privileges to configure a mirror set. To configure a mirror set:

1. Click Start, point to Programs, point to Administrative Tools (Common), and
   then click Disk Administrator.

   If a Disk Administrator dialog box appears, indicating that this is the first
   time that Disk Administrator has been run, click OK.

   If a Confirm dialog box appears, click Yes to write a signature to the disk.
   If additional Confirm dialog boxes appear, click Yes in each one.

2. In the Disk Administrator dialog box, click the partition that you want to
   mirror. Press and hold CTRL while you click the area that is marked Free
   Space on the additional disk that will be used for the mirror set, and then
   release the CTRL key.

3. In the Disk Administrator dialog box, click Establish Mirror on the Fault
   Tolerance.

   If a Disk Administrator dialog box is displayed, indicating that this is a
   mirror set of the boot partition, click OK.

4. In the Disk Administrator dialog box, click Commit Changes Now on the
   Partition menu. In the Confirm dialog box, click Yes.

   If another Confirm dialog box is displayed, click Yes. In the Disk
   Administrator dialog box, click OK.

   If another Disk Administrator dialog box is displayed, click OK to shut down
   and restart your computer.

5. Because your computer's disk configuration has changed, it is recommended
   that you use the Rdisk.exe utility to create a new Emergency Repair disk.

   In addition, if you have mirrored the partition that contains your Windows NT
   Server 4.0 system files (sometimes called the "boot partition"), it is
   recommended that you create a fault-tolerance boot disk.

REFERENCES
==========

For additional information about how to use Rdisk.exe to create a new Emergency
Repair disk, click the article number below to view the article in the Microsoft
Knowledge Base:

   Q158866 How to Manually Create an Emergency Repair Disk

For additional information about how to create a fault-tolerance boot disk, click
the article number below to view the article in the Microsoft Knowledge Base:

   Q119467 How to Create a Bootable Disk for an NTFS or FAT Partition

Additional query words:

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Keywords          : kbenv kbhw kbtool kbAudITPro kbHOWTOmaster 
Technology        : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400
Version           : :4.0
Issue type        : kbhowto

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