Disk mirroring windows 2008

From the above information it is clear that Volume 2 is MB in size. In order to be able to mirror this volume, a disk with at least MB is required. Clearly, disk 2 meets this requirement. Therefore, all that needs to be done is to add disk 2 as the mirror disk for our volume using the add disk command.

Note that if the disks are not dynamic disks they will need to be converted with the convert dynamic command:. At this point Windows Server will begin the resynching process which, depending on the size of the volume being mirrored may take some time. This fact is reported by the show volume command which lists the volume as being of type Mirror with a status of Rebuild.

Once the resynching process is complete the status will be displayed as Healthy. A Windows Server mirror may be broken which creates two separate and independent volumes containing identical data or removed which removes the data on the mirror leaving free space on the designated mirror disk. To break a mirror from the Disk Management snap-in right click on one of the volumes in the set in graphical view and select Break Mirrored Volume from the pop-up menu.

To break a mirror set from the command line use the break command, specifying one of the two disks in the mirrored set:. To remove a mirror from a mirrored set, removing all mirrored data and leaving free space on the disk right click on the mirror volume to be removed in the Disk Management graphical view and select Remove Mirror.

If one of the disks in a mirrored set fails the good news is that, unlike striped volumes, all the data is still present on the remaining healthy disk this, after all is the whole point of disk mirroring. In this situation, however, it is important to replace the faulty disk and rebuild the mirror before the healthy drive also fails. To achieve this right click on the failed volume and select Remove Mirror. Next, identify a suitable alternate or newly installed drive with sufficient space to act as a mirror.

Right click on the existing, healthy volume from the original mirrored set, select Add Mirror from the resulting menu, select the new disk in the Add Mirror dialog and click on Add Mirror. Unlike the master boot record MBR mirrors on bit versions of Windows, there are more steps to successfully create and to start mirrored boot volumes on GPT disks. This article also describes how to recover after a primary disk failure. You must have the built-in Diskpart. You can use the Disk Management console do some of these tasks.

But for other tasks, you have to use the built-in Diskpart. For consistency and for ease of use, this article uses the Diskpart. For help with any of the Diskpart. The steps that are described in the procedures in this article use real examples. The procedures in this article show the expected results that each command returns. In these procedures, disk 0 is the primary system and the boot drive, and disk 1 is the secondary drive. The EFI partition contains the system files that are used to start the operating system.

The disk must have an EFI partition to start. If the primary system drive disk 0 fails, you can use the EFI partition on the secondary drive disk 1 to start the operating system. You can use only the Diskpart. Before you start the following procedure, make sure that you have another basic disk that has unallocated free space that is greater than or equal to the capacity of the system and boot partitions of the primary disk.

If you already converted the spare drive to a dynamic disk, revert it back to a basic drive before you follow these steps. This starts the diskpart console. The diskpart console is now ready for input commands. Select the disk that you want to be the secondary drive, and then convert the drive to GPT. In this example, disk 1 is used for the mirror secondary drive. The disk that you select must not contain any data partitions.

Additionally, the disk must be a raw basic disk that has unallocated space that is greater than or equal to the capacity of the primary system disk. The following are the commands that you type at the command prompt. The commands are formatted in bold, and the comments about the command or about the contents of the screen display are formatted in plain text.

If you notice that more than one partition is displayed, you have selected the wrong drive, or you did not start with a raw drive. Correct this before you continue, or data loss may occur. Next, we need to select the system volume on disk 0. To obtain a list of volumes, select the disk and use the list volume command:. In the above example the system volume is listed as Volume 0. This will initiate the resynching process which may take some time depending on the size of the system volume.

When a list volume command is run during this process, the volume status will be listed as Rebuild until the resynching is complete:. When the Status changes to Healthy the mirroring is complete. Next time the system is rebooted the mirror will be listed in the boot menu as Microsoft Windows Server - secondary plex.

For the purposes of this tutorial we will be working with a system containing a GPT system disk and a new disk numbered as disks 0 and 1 respectively.

The objective will be to mirror the GTP system disk on disk 1. The mirroring process will be performed from the command prompt using the diskpart tool which can be launched by opening a command prompt and typing diskpart.

In the above output, disk 0 is the system disk and disk 1 is the new disk which will be used as the mirror. Before disk 1 can be used, any existing partitions on that disk must be removed. To identify any current partitions, select this disk and list partitions as follows:. Clearly, this disk already contains a partition. If this data is required, be sure to back it up before removing any partitions. Once the backup is complete, select and delete any partitions as follows:.

Since the disk no longer contains any partitions this can be now be achieved using the convert command:. If there is a failure of the primary drive disk 0 , you must start the computer in the secondary drive disk 1 , and then re-create the mirror to return the boot volume to a fault-tolerant state. To do this, follow these steps. Replace the failed dynamic disk 0 by using the directions that are provided by your hardware vendor.

Make sure that the disk has no partition information. The diskpart clean command can be used to destroy any existing partition information on the disk. Be careful when you run the diskpart clean command because it will destroy the partition table on the selected disk, and it will make the contents of the disk inaccessible. Throughout this section, the former primary disk will continue to be known as disk 0, and the former secondary disk will continue to be known as disk 1.

However, after you follow these steps, disk 1 will be the new primary disk, and disk 0 will be the new secondary disk. If you running a pre-R2 version of Windows Server , install the hotfix that is described in the following Microsoft Knowledge Base article, and restart the computer when you are prompted.

Note This fix is included in Windows Server R2. Therefore, you do not have to install it on computers that are running Windows Server R2. This sets the BCD store on disk 1 as the active system store, and lets it be modified. Run the following commands to select the EFI partition on disk 1, and to assign to it drive letter "S. You have to break the broken mirror.

However, you must first determine which is the correct disk on which to run the diskpart break command. After you do this, select the mirror volume Volume , and then view the details to determine from which missing disk m you have to break the mirror. Remove all stale entries from the BCD store to return the system to a known clean state. Also, rename the entries to accurately reflect the current state of the system.

Restart the computer. Convert the newly added disk to GPT format, and then create the partition structure. Duplicate the layout of disk 1 on disk 0. Wait for the mirror resynchronization to finish. You can use Disk Management to check on the resynchronization process.

Record the GUID for the new entry that is given in the output for this command. Note By default, the boot entries will point to disk 1. If you boot from disk 0, and If you have to modify the BCD store when you start in disk 0, you first have to import the store:. Need more help? Expand your skills.