Modern Public Folders are a hot topic at the moment. The revised limits for supportability are a talking point for many businesses – especially around the current 10,000 folder limit (which should be raised to 100,000 and beyond in CU6).
It means many admins are having to fully understand their legacy Public Folder estate prior to moving them to Modern Public Folders, or simply leaving them on legacy platforms (with caveats) if their Public Folder estate is simply too large for Exchange 2013 to reliably handle.
Adding to this frustration is the fact that you can only move Public Folders in a 'cross forest' scenario to Office 365 at this time. Native support for cross forest moves of Public Folders simply isn't there.
So, providing you fall within the supportability metrics for Modern Public Folders, and you need to migrate cross forest, how do you do this at this time?
One product I have tested with great success is Mail Attender by Sherpa Software.
In my example below I am going to move Public Folder content from Forest A, running Exchange 2007 SP3 to Forest B, with Exchange 2013 CU5.
- For the actual migration server I am using a Windows 7 x64 virtualised desktop with Office 2013 installed. The Desktop is domain joined and in Forest B.
- I have used PfDavAdmin/exfolders to give a mailbox in Forest A account OWNER permissions across the entire Public Folder tree in Forest A.
- A Modern Public Folder has been created with a single empty folder, I have given a mailbox in Forest B OWNER permissions on this folder.
- A forest trust exists between Forest A and Forest B
Run setup.exe and select a complete installation
It will ask you for a service account to run under. I selected an Exchange Administrator account in Forest B (the same Forest this desktop is domain joined).
It will then automatically grant the relevant log on as a service rights.
Ensure you start the service
Once installation is completed, restart the desktop and then open the Mail Attender console and confirm the service has started
Open Outlook 2013 (Office/Outlook 2007/2010 is also supported) and create two new profiles.
One should be to the mailbox in Forest A – connecting to the legacy Public Folders that the account has OWNER permissions over.
The other connect to Forest B and Exchange 2013.
I have called the profiles E12_PF and E15_PF:
In Exchange 2013 – ensure the account has OWNER permissions on the tree
Now we're ready to start setting the Source and Target profiles up in Mail Attender. Within Mail Attender itself go to:
Email Store | Public Folders | Add Public Folders from Global Addres List | Select your source profile (in my case E12_PF)
You will now have this listed under 'All Known Public Folders'
We will now do the same for the Target Profile, selecting the E15_PF mailbox.
I now have both my Source and Target profiles in Mail Attender:
We must now ensure that the service account running the Mail Attender service has full mailbox access to the Exchange 2013 mailbox in Forest B as well as the mailbox in Forest A.
As this is 'cross forest' where the service account is in Forest B and the Exchange 2007 Source mailbox is in Forest A we need to add the permission via powershell. I am also assuming you have a Forest Trust in place between both Forests as noted in the pre-requisites.
Using the Exchange 2007 EMS:
Add-MailboxPermission –Identity 'CN of Mailbox' –User 'ForestB\Administrator' –AccessRights 'FullAccess'
We now add the service account to the Exchange 2013 mailbox also. You can do this in the EAC or again via powershell.
Once full mailbox access has been granted, we can run statistic collections in Mail Attender. These will tell us we can connect to both the Source and Target Public Folders. Simply right click each known public folder store and select 'Collect Statistics Now'.
Providing there are no issues when collecting the statistics this means the Mail Attender console can log in to both Outlook profiles and see the public folder tree.
We are now ready to start creating some migration rules.
The process is fairly straight forward. Give it a name:
Add the Source Exchange 2007 endpoint in the 'Email Store' tab
Now select the 'Folders' tab. Select for 'this rule applies to' "ONLY those Folders Listed below" additionally select the 'Explicit Folder Path and Name' and put in your folder Entry. For examples "\All Public Folders\E12 Migration Top level folder". Ensure you include all sub folders.
You can do cool additional things like take data from the Dumpster.
Moving on to the 'Conditions' tab – I haven't selected anything here, but you can add some pretty powerful conditions here. For example maybe you only want to take the last 5 months worth of Public Folder data? Or you want to delete any attachments? Or you just want to migrate certain types of data? Well you can add rules like that here.
Moving on to the 'Actions' tab this is where you select how the data is transferred. I am selecting here 'Copy Message to Public Folder'
Within the action is where we specify the Target Outlook profile – this is pretty confusing at first as it isn't very intuitive!
Note: You have to put "[FOLDER_PATH_FROM(3)]" in, this is how it copies the child folders from the source to the target. Again this isn't intuitive, I recieved this information from a support call.. If you don't do this you'll only copy over the top level folder.
Once you press OK that's the migration rule created.
You will now see this show up as standard rule under the Mail Attender Rule set.
You can add a schedule having the data move multiple times a day if you want. Something that I used to rely on when using the InterOrg Replication tool For Exchange 2003 to Exchange 2003/2007 and 2010 cross forest public folder migrations.
You can additionally configure two way synchronisation, if you are going to be in a long period of co-existence.
Now run the rule and it will copy and migrate your Public Folder data. This may take some time depending on the amount of data and number of Public Folders. I again urge you to be aware of the current revised limits for supportability for Exchange 2013 up to CU5.
For those that need something to perform cross forest public folder migrations to Exchange 2013 on-premises right now, this tool provides that. It is unknown if and when Microsoft will update Exchange 2013 to finally support on-premise cross forest Public Folder moves.
There are simpler, less autonomous ways of moving the data, but these typically include PST digestion and Exchange 2013 doesn't currently support PST imports or exports to modern public folder mailboxes – so the whole affair will be wholly Outlook driven – which isn't ideal.
If you want the solution to be automated, run on schedules, support bi-directional replication, and include some powerful technology to autonomously clean up your data when migrating to Exchange 2013, Mail Attender is a pretty good product.
Watch out for Part 2 where I'll show you how to script your permissions and configure your mail enabled Public Folders.
Oliver Moazzezi - MVP Exchange Server