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Configure AutoReseed for a database availability group

 

Applies to: Exchange Server 2013

Topic Last Modified: 2013-04-15

AutoReseed is a feature for quickly restoring database redundancy after a disk failure. If a disk fails, the database copies stored on that disk are automatically reseeded to a preconfigured spare disk on the Mailbox server. You can use the steps in this topic to configure AutoReseed for a database availability group (DAG).

CautionCaution:
The AutoReseed feature doesn't perform any prerequisite configuration tasks for you. Installing disks correctly, adding spare disks to the system, replacing bad disks, and formatting new disks must be done manually by an administrator.

For additional management tasks related to DAGs, see Managing database availability groups.

  • Estimated time to complete this task: 10 minutes.

  • You need to be assigned permissions before you can perform this procedure or procedures. To see what permissions you need, see the "Database availability groups" entry in the High availability and site resilience permissions topic.

  • A single logical disk/partition per physical disk must be created.

  • The specific database and log folder structure described in the steps below must be used.

  • For information about keyboard shortcuts that may apply to the procedures in this topic, see Keyboard shortcuts in the Exchange admin center.

TipTip:
Having problems? Ask for help in the Exchange forums. Visit the forums at: Exchange Server, Exchange Online, or Exchange Online Protection..

The first step involves configuring the root directories for the databases (AutoDagDatabasesRootFolderPath) and volumes (AutoDagVolumesRootFolderPath) used by the DAG. The defaults are C:\ExchangeDatabases, and C:\ExchangeVolumes, respectively. You can omit this step if you're using the default paths.

This example illustrates how to configure the root path for the databases.

Set-DatabaseAvailabilityGroup DAG1 -AutoDagDatabasesRootFolderPath "C:\ExchDbs"

This example illustrates how to configure the root path for the storage volumes.

Set-DatabaseAvailabilityGroup DAG1 -AutoDagVolumesRootFolderPath "C:\ExchVols"

To verify that you've successfully configured the root paths for databases and volumes, run the following command.

Get-DatabaseAvailabilityGroup DAG1 | Format-List *auto*

The output for AutoDagDatabasesRootFolderPath and AutoDagVolumesRootFolderPath should reflect the configured paths.

Next, configure the number of databases per volume (AutoDagDatabaseCopiesPerVolume) for the DAG.

This example illustrates how to configure this AutoReseed setting for a DAG configured with 4 databases per volume.

Set-DatabaseAvailabilityGroup DAG1 -AutoDagDatabaseCopiesPerVolume 4

To verify that you've successfully configured the number of databases per volume, run the following command.

Get-DatabaseAvailabilityGroup DAG1 | Format-List *auto*

The output for AutoDagDatabaseCopiesPerVolume should reflect the configured value.

Next, create the directories that correspond to the root directories you configured in Step 1. This example shows how to create the default directories using the command prompt.

md C:\ExchangeDatabases
md C:\ExchangeVolumes

To verify that you've successfully configured the root directories for databases and volumes, run the following command.

Dir C:\

The created directories should appear in the output list.

For every volume that will be used for databases (including spare volumes), use the Windows Disk Management application (diskmgmt.msc) to mount each volume in a mounted folder under C:\ExchangeVolumes\. For example, if there are 2 volumes with databases and 1 spare volume, mount the volumes to the following mounted folders:

  • C:\ExchangeVolumes\Volume1

  • C:\ExchangeVolumes\Volume2

  • C:\ExchangeVolumes\Volume3

The names of the mounted folders can be any folder name, as long as the folders are mounted under the root volume’s path.

To verify that you've successfully mounted the volume folders, run the following command.

Dir C:\

The mounted volumes should appear in the output list.

Next, create the database directories under the root path C:\ExchangeDatabases. This example illustrates how to create directories for a storage configuration with 4 databases on each volume.

md c:\ExchangeDatabases\db001
md c:\ExchangeDatabases\db002
md c:\ExchangeDatabases\db003
md c:\ExchangeDatabases\db004

To verify that you've successfully mounted the database folders, run the following command.

Dir C:\ExchangeDatabases

The created directories should appear in the output list.

Create the mount points for each database and link the mount point to the correct volume. For example, the mounted folder for db001 should be at C:\ExchangeDatabases\db001. You can use diskmgmt.msc or mountvol.exe to do this. This example illustrates how to mount db001 to C:\ExchangeDatabases\db001 using mountvol.exe.

Mountvol.exe c:\ExchangeDatabases\db001 \\?\Volume (GUID)

To verify that you've successfully created the mount points for the database, run the following command.

Mountvol.exe C:\ExchangeDatabases\db001 /L

The mounted volume should appear in the mount point list.

Next, create two directories underneath the folders you created in Step 5, one for each database and one for each of the database's log stream that will be stored on the same volume. You must use the following format for your directory structure:

C:\< DatabaseFolderName>\DatabaseName\<DatabaseName>.db

C:\< DatabaseFolderName>\DatabaseName\<DatabaseName>.log

This example illustrates how to create directories for 4 databases that will be stored on Volume 1:

md c:\ExchangeDatabases\db001\db001.db
md c:\ExchangeDatabases\db001\db001.log
md c:\ExchangeDatabases\db002\db002.db
md c:\ExchangeDatabases\db002\db002.log
md c:\ExchangeDatabases\db003\db003.db
md c:\ExchangeDatabases\db003\db003.log
md c:\ExchangeDatabases\db004\db004.db
md c:\ExchangeDatabases\db004\db004.log

Repeat the preceding commands for databases on every volume.

To verify that you've successfully created the database directory structure, run the following command.

Dir C:\ExchangeDatabases /s

The created directories should appear in the output list.

Create databases with log and database paths configured with the appropriate folders. This example illustrates how to create a database that's stored in the newly created directory and mount point structure.

New-MailboxDatabase -Name db001 -Server MBX1 -LogFolderPath C:\ExchangeDatabases\db001\db001.log -EdbFilePath C:\ExchangeDatabases\db001\db001.db\db001.edb

To verify that you've successfully created databases in the appropriate folder, run the following command.

Get-MailboxDatabase db001 | Format List *path*

Database properties that are returned should indicate that the database file and log files are being stored in the above folders.

To verify that you've configured AutoReseed for a DAG, do the following:

  1. Run the following command to verify the DAG is configured correctly.

    Get-DatabaseAvailabilityGroup DAG1 | Format-List *auto*
    
  2. Run the following command to verify the directory structure is configured correctly (below are the default paths; if necessary, substitute the paths for the paths you're using).

    Dir c:\ExchangeDatabases /s
    
    Dir c:\ExchangeVolumes /s
    
 
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