Configure AutoReseed for a database availability group
Applies to: Exchange Server 2016
Topic Last Modified: 2016-08-23
Summary: 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 Exchange 2016 server.
Use the steps in this topic to configure AutoReseed for a database availability group (DAG) in Exchange 2016.
|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.
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.
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
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
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:
The names of the mounted folders can be any folder name, as long as the folders are mounted under the root volume’s path.
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.
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)
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:
This example illustrates how to create directories for 4 databases that will be stored on Volume 1:
Repeat the preceding commands for databases on every volume.
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:
Run the following command to verify the DAG is configured correctly.
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