Scripting the Removal of all Databases from a DAG

Most of you may never need to do this task, but if you like I, have a staging or lab environment you may find yourself doing this from time to time. In my particular case, I decided to rebuild all the databases in all 3 of my DAGs once I installed SP1. I only have 100 users on the platform and once we move to SP1, we will begin migration of the remaining 33,000 mailboxes, so this would be my only chance to do this. Some may think this is unnecessary, but I’ve put these servers through a lot of hard testing and I want to ensure my users have a nice clean database when we move them.

Mailbox Migrations

When thinking of the best way to remove the all the databases, there were many questions I asked myself and then validated in my lab. One hurdle was how do I move all the users from a DAG? This can be done relatively easy, but in production I have 120 databases and I don’t want to cherry pick the target database. Exchange 2013 has a workflow that will choose the databases and I wanted to leverage that process in the move. Before I can allow this process I needed to isolate the DAGs I was targeting for deletion to ensure mailboxes were migrated to only the DAG I was not. This little script did the job nicely

Get-MailboxDatabase | ?{$_.MasterServerOrAvailabilityGroup -eq "DAG-NAME"}` 
| Set-MailboxDatabase -IsExcludedFromProvisioning $true 

Once isolated, I ran a script to dump all mailboxes to a CSV and import it back into a New-MigrationBatch. I’m not as proficient as PowerShell as I would like to be, so if anyone has some thoughts on simplification, I welcome the advice.

$Databases = Get-MailboxDatabase | ?{$_.MasterServerOrAvailabilityGroup -eq "DAG-NAME"}
$path = "C:\DAG-MBXExport.csv"

ForEach ($Database in $Databases) {
       Set-ADServerSettings -ViewEntireForest $true
       Get-Mailbox -Database $database.Name | ForEach-Object {
           $users = $_.PrimarySMTPAddress
           New-Object -TypeName PSObject -Property @{EmailAddress = $users
       } | Select-Object EmailAddress
   } | Export-Csv $path -NoTypeInformation -append

       Get-Mailbox -Database $database.Name -Arbitration | ForEach-Object {
           $Arbitration = $_.PrimarySMTPAddress
           New-Object -TypeName PSObject -Property @{EmailAddress = $Arbitration
       } | Select-Object EmailAddress
   } | Export-Csv $path -NoTypeInformation -append
New-MigrationBatch -Name "DAG-Migration-Batch" -local -CSVData ([System.IO.File]::ReadAllBytes($path))

If you want to autostart the batch and autocomplete, just add the parameters -AutoStart or -AutoComplete at the end of the New-MigrationBatch line. You can also add other parameters referenced in this link.

Database Removal

Every mailbox should now be removed from your DAG, so now you can prepare for deleting all database copies. Now, I could have come up with a couple of scripts to do the job, but I like doing things the hard way, so I did it all in one. The following script will disable circular logging if enabled and deleted all the databases currently not mounted, then go back and remove the last database copy for that DB. There is a known issue when removing a database and getting an error when trying to delete the monitoring mailbox, apparently Exchange Trusted Subsystem doesn’t have rights to the Monitoring Mailboxes OU, so it is on my list of things to do to add some functionality to compensate. I’ve tested this script on a DAG with 120 databases across 10 DAG members each having 5 copies and it worked really well.

.Author: Mike DiVergilio, Senior Systems Engineer, Cox Communications

.Date: 4/4/2014

    Script to remove all database copies from an Exchange 2013 DAG

    Current Build: 1.0

    This script performs the process of disabling circular logging on each database, blocking 
    activation to ensure a switchover does not occur during this time and then remove all 
    passive and active copies

Function remove_lastcopy(){

ForEach($Server in $Servers){

    $LastDatabases = Get-MailboxDatabase -Server $Server.Identity
    foreach($LastDatabase in $LastDatabases){
        Write-Host "Removing Last Database Copy" $LastDatabase.Name "on Server $Server" -ForegroundColor Red
        Remove-MailboxDatabase $LastDatabase.Name -Confirm:$false
        Start-Sleep 5
Function disable_circularlogging(){

$CircularLogDBs = Get-MailboxDatabase -Server $Server.Name

    If($CircularLogDBs.CircularLoggingEnabled -eq $true){
    ForEach($CircularLogDB in $CircularLogDBs){
         Write-Host "Note: Disabling Circular Logging on database $CircularLogDB" -ForegroundColor Yellow
         Set-MailboxDatabase -Identity $ -CircularLoggingEnabled $false
    Write-Host "Note: Circular Logging Disabled on all Databases for Server $Server" -ForegroundColor Yellow

$Servers = Get-MailboxServer| ?{$_.DatabaseAvailabilityGroup -eq "DAGName" }

ForEach($Server in $Servers){

Set-MailboxServer $Server.Identity -DatabaseCopyAutoActivationPolicy Blocked
$DatabaseCopies = Get-MailboxDatabaseCopyStatus -Server $Server.Identity | select DatabaseName,Name,Status

ForEach($Database in $DatabaseCopies){

    if($database.status -ne "Mounted"){
          Write-Host "Removing Database Copy" $Database.DatabaseName "on Server $Server" -ForegroundColor Green
          Remove-MailboxDatabaseCopy $Database.Name -Confirm:$false
          Start-Sleep 5
    Write-Host "Database" $Database.DatabaseName "is Mounted, Skipping..."
Start-sleep 300

Once completed, you will need to remove the EDB and Log files if you decide not to just blow it all away via the Storage Calculator Diskpart script. I may also look into adding this in a future update. I hope someone out there benefits from this process, I know I did when faced with the option of doing this manually or through.


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