Книга: Windows Server 2012 R2 Storage, Security, & Networking Pocket Consultant

Repairing a mirrored system volume to enable boot

Repairing a mirrored system volume to enable boot

The failure of a mirrored drive might prevent your system from booting. Typically, this happens when you’re mirroring the system or boot volume, or both, and the primary mirror drive has failed. In previous versions of the Windows operating system, you often had to go through several procedures to get the system back up and running. With Windows Server 2012 R2, the failure of a primary mirror is usually much easier to resolve.

When you mirror a system volume, the operating system should add an entry to the system’s boot manager that allows you to boot to the secondary mirror. Resolving a primary mirror failure is much easier with this entry in the boot manager file than without it because all you need to do is select the entry to boot to the secondary mirror. If you mirror the boot volume and a secondary mirror entry is not created for you, you can modify the boot entries in the boot manager to create one by using the BCD Editor (Bcdedit.exe).

If a system fails to boot to the primary system volume, restart the system and select the Windows Server 2012 R2-Secondary Plex option for the operating system you want to start. The system should start up normally. After you successfully boot the system to the secondary drive, you can schedule the maintenance necessary to rebuild the mirror as described in the following steps:

1. Shut down the system, and replace the failed volume or add a hard disk drive. Then restart the system.

2. Break the mirror set, and then re-create the mirror on the drive you replaced, which is usually drive 0. Press and hold or right-click the remaining volume that was part of the original mirror, and then tap or click Add Mirror. Next, follow the technique in “Mirroring an existing volume” earlier in the chapter.

3. If you want the primary mirror to be on the drive you added or replaced, use Disk Management to break the mirror again. Be sure that the primary drive in the original mirror set has the drive letter that was previously assigned to the complete mirror. If it doesn’t, assign the appropriate drive letter.

4. Press and hold or right-click the original system volume, and then tap or click Add Mirror. Now re-create the mirror.

5. Check the boot entries in the boot manager and use the BCD Editor to ensure that the original system volume is used during startup.

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