Applying "Multiple" or “Housekeeping” retention policies to the end users- Exchange 2010/2013

From: 

http://www.proexchange.be/blogs/exchange2010/archive/2011/08/26/applying-housekeeping-retention-policies-to-the-end-users.aspx

In my previous blog post I wrote about a basic retention policy for doing some basic housekeeping using Exchange 2010 retention policies. The last sentence of that post post reads:

All there’s is left to do is applying the policy to the remainder of the user base, but don’t forget to skip the CEO’s mailbox ;-)

Right now you’re probably thinking “Get-Mailbox | Set-Mailbox” does the trick. Obviously it does the trick; but I’ve got a couple more requirements.

The retention policy needs to be set on about 2500. If you’re like me that you rather spend halve a day writing a script than using that time to make the changes in the GUI. (+ I wouldn’t have something to blog about.)

I’ve got that CEO mailbox to exclude. I could of course easily exclude a single mailbox. Let’s make it a bit more future proof and ensure the scripts can deal with multiple exclusions.

It’s also a good idea to filter mailboxes out which already have a retention policy set. The policy will need to be applied to future mailboxes as well. Obviously I can request the service desk to update their user/mailbox creation procedures. However as an exchange admin I prefer to keep control. In other words we need something that we can run over and over again.

Lets go over the different sections of the script:

First of all we start with defining the list of excluded mailboxes. I chose to use a lengthy way of doing so. This way I could add sufficient comments to ensure it’s really clear which VIPs we’re dealing with (as there is no logical connection between the alias and the user).

# Defining the mbx to be excluded from the retention policy
# You can add to the list as needed
# However make sure you use the alias, not SamAccountName!
$Exceptions = @() # Define array
$Exceptions += "ABC123" # Casper
$Exceptions += "DEF456" # Melchior
$Exceptions += "GHI789" # Balthazar

After Some more variable definitions, we convert the exclusion list form an array of strings to an array of mailbox object (needed later on in the script). Afterwards we print a list on screen showing the list of excluded mailbox.

# Set more variables
$RetPol = "Remove old deleted items and calendar entries"
$TableCols = "Alias","DisplayName","RetentionPolicy"
# Display Exclusions
Clear-Host
Write-Host "Retention Policies will NOT be changed for:" -ForegroundColor Red
$Exceptions = $Exceptions | Get-Mailbox # Convert array of strings to array of mbx objects
$Exceptions | ft $TableCols

The next section does a query for mailboxes for which not Retention Policy has been set yet.

# Exclude mbx which already have the retention policy set
Write-Host "`nBuilding the list of mailboxes without a Retention Policy set" -ForegroundColor Green
$MBX = @() # Define array
$MBX += $(Get-Mailbox -ResultSize Unlimited | where {!$_.RetentionPolicy}) # Exclude mailboxes which have already a retention policy set
$MBX | ft $TableCols
Write-Host "`nPlease check if these counts seem realistic to you." -ForegroundColor Green
Write-Host "# of mbx on the exclusion list:" $Exceptions.Count
Write-Host "# of mbx without retention policy:" $MBX.Count

We compare the array of mbxs without retention policy with the exception list. We converted the exception list earlier on to be able to compare of objects of the same type. The delta is the list of mailboxes we need to update. The PassThru-parameter is need to ensure our command returns mailbox objects because the Compare-Object command returns “difference objects” by default. The SideIndicator property on the other hand excludes results that are in $Exceptions but not $MBX, which can happen if you do some creative testing.

# Exclude mbx on the exclusion list
$MBX2Set = @() # Define array
$MBX2Set += $(Compare-Object $MBX $Exceptions -PassThru | ? { $_.SideIndicator -eq "<="})
$MBX2Set | ft $TableCols

Last but not least we need to actually set the Retention Policies for the remaining mailboxes.

#Setting RetentionPolicy
Write-Host "`nSetting retention policy" -ForegroundColor Green
if ($MBX2Set) {
    Write-Host "# of mbx to set retention policy for:" $MBX2Set.Count
    $MBX2Set | Set-Mailbox -RetentionPolicy $RetPol
    } else {
    Write-Host "No mailboxes to set!" -ForegroundColor Yellow
}

Screenshots of scripts don’t always offer a lot of added value, especially if they read “nothing to change” but at least one can admire the colors ;-)