​How do I find the size of Source Public Folders?

Answer:

The simplest way to determine the size of your Source Public Folders is to run a PowerShell query to obtain the size-related statistics from your Public Folders.

Here is an example script that will pipe the results into a file named PFStatistics.csv. You can then use this information to break up your Public Folders into smaller-sized Public Folders.

Get-PublicFolderStatistics -ResultSize Unlimited | Select-Object Name,FolderPath, AssociatedItemCount, DeletedItemCount, ItemCount, TotalAssociatedItemSize, TotalDeletedItemSize, TotalItemSize | Export-csv .\PFStatistics.csv -NoTypeInformation

Notes:

• If your Source is Exchange 2007, and any Public Folders contain more than 20,000 items, these should be broken into multiple Public Folders.
• If your Source is Exchange 2010 or later, and any Public Folders contain more than 100,000 items, these should be divided into multiple Public Folders.
• The Microsoft TechNet article here provides further detail on Microsoft Public Folder size limitations.