Announcing the support for modern public folder migrations without dumpster data


Long time Exchange administrators will remember that Exchange Server had a feature that was for a while unceremoniously referred to as the “dumpster”. We have since renamed the feature to a more descriptive Recoverable Items Folder. This blog post also contains a bit of history of this feature for those interested.

Up to now, during public folder migration, all the public folder data including dumpsters was migrated from on-premises servers to the cloud. Administrators did not have an option to exclude this data at migration.

We are introducing the ability to migrate public folders to cloud without migrating the dumpster data. To do this, administrators need to pass the ExcludeDumpsters parameter while creating the migration batch. This option can be used when source server version is Exchange 2013 or 2016. Here is an example of how to use this parameter:

New-MigrationBatch -Name PublicFolderMigration -CSVData $bytes -SourceEndpoint $PfEndpoint.Identity -ExcludeDumpsters

Why would you want to do this?

Excluding this data can help you scale your public folder migration if you do not need the data to come over. This will result in faster public folder migration as the amount of data that will need to be migrated is going to be smaller.

To check the dumpster folders size, you can run the following:

Get-PublicFolder \NON_IPM_SUBTREE\DUMPSTER_ROOT -Recurse -ResultSize:unlimited | ?{$_.FolderClass -ne "$null"} | ft name,foldersize

In addition to size consideration, we have seen some organizations where dumpster data got corrupted (for various reasons) and administrators did not want that corrupted data migrated to cloud. If you find yourself in that situation, this feature will enable you to leave that data behind.

The obvious drawback to doing this is that users will lose the ability to recover items that were previous deleted from public folders (pre-migration).

Note: The ExcludeDumpsters parameter is optional and if not passed to migration batch, all dumpsters will migrate to cloud. Once you choose to exclude dumpsters and the migration is finalized, there is no way to go back and re-include the dumpsters into cloud public folders. If, during the migration in which you used the ExcludeDumpsters parameter, you decide that you do want to migrate the dumpsters data to the cloud, remove the current migration batch and create another without the ExcludeDumpsters parameter.

This option can be added at point 4 of Step 7 in below TechNet articles for public folder migration (we will work to change the documentation next):

Keep checking this blog for further updates on the subject!

In case of any questions, please do reach out to us via the comments section below.

Public folder team

Comments (2)

  1. am12375 says:

    What is the expected behavior if someone recovers/restores a deleted public folder from the dumpster during the synchronization process (prior to cut over), if the batch was created using the -ExcludeDumpsters parameter? Is this supported, or will there be any impact to the PublicFolderMailboxMigrationRequest?

    1. Mithun says:

      if the dumpster is excluded and user recovers a folder from dumpster. you will see a message in migration report a new folder was recovered with folder path for admin to do the need full action with that folder.

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