Public Folder Updates in Exchange 2013 CU6: Improving Scale and More


Note: Some of the documentation referenced may not be fully available at the time of publishing of this post.

Exchange Server 2013 Cumulative Update 6 (CU6) was released today and provides several important updates for modern Public Folders. This blog post introduces you to the updates delivered in CU6 and discusses our on-going investments in public folders.

10x Increase in Public Folder Limits

CU6 delivers the first round of investments we have made to scale up the limits for Public Folders in Exchange Server 2013. CU6 raises the folder count limit to 100,000 folders. This is a 10x increase over the prior limit as defined in the Exchange Server 2013 limits for public folders. This enables you to migrate and deploy larger Public Folder hierarchies on premises with Exchange Server 2013. Customers can immediately take advantage of this new scale by deploying CU6.

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In addition to the increased folder scale capabilities CU6 delivers improvements for concurrent access of Public Folders by reducing lock contention in store for hierarchy sync and content mailbox access.

As you scale the number of public folders in Exchange you might need to keep track of the number of folders that have been created. Exchange PowerShell provides an easy way to see the current public folder count in Exchange Server 2013. Using the Get-PublicFolder and Measure-Object cmdlets you can readily get a current count of your public folders created in Exchange 2013.

Get-PublicFolder –Recurse –ResultSize Unlimited | Measure-Object
Count    : 40051
Average  :
Sum      :
Maximum  :
Minimum  :
Property :

Mail-Enabled Public Folder Permission Changes

This is an important change for customers already using Public Folders in Exchange Server 2013. Prior to CU6 unauthorized senders were able to send messages to mail-enabled Public Folders which means external users could send email to mail-enabled Public Folders regardless of permissions. With CU6, administrators must grant Anonymous users Create Items permissions in the mail-enabled Public Folder to allow external users the ability to send email to the mail-enabled Public Folder. Refer to the CU6 release notes Public Folders section for guidance on updating your configuration.

Automatic Public Folder mailbox readiness management after migration

An additional change delivered in CU6 for Public Folders helps improve the administrator experience post migration. All PF mailboxes serve hierarchy by default in Exchange Server 2013. We have introduced new logic to check if the hierarchy is fully synced to a mailbox after migration. If it is, then the mailbox is automatically made available to serve public folder hierarchy connection else we wait for full sync to complete. This eases work for admin to manually manage readiness of a mailbox after migration completes. Admins can still turn hierarchy serving off and on (default = on) as they please. Refer to the Public Folder article for specific attributes to control hierarchy sync.

Public Folder Deployment Guidance

The increased scale capabilities for public folders in CU6 enables more advanced configurations to begin migrating to modern Public Folders. To meet the needs of these large scale migrations the team has created deployment guidance to assist customers migrating larger scale public folder hierarchies. This deployment guidance will become available in the next few weeks. We will update this post with a link once it is available.

What’s Next

This is the first round of public folder scale improvements we are working to deliver as we shared in the prior Exchange team blog post. Scale improvements are targeted to increase again in a future update. Scale improvements will remain our top priority for Public Folder updates. Other updates such as OWA support for calendar and contacts and Public Folder reporting tools are expected to follow after delivering further scale updates.

Brian Shiers
Technical Product Manager

 

Frequently asked questions

Q: Is there a limit for the number of sub-folders within a single public folder?
A: The recommended maximum number of sub-folders is 1000. This is the level that has been validated and is the same limit used in Exchange Online.

Q: Is there a limit for the folder depth of the hierarchy?
A: The recommended maximum depth of the hierarchy is 300 folder levels. This is the level that has been validated and is the same limit used in Exchange Online.

Q: Does the increase in folder count change the number of public folder mailboxes or quota for public folders?
A: The number of public folder mailboxes and the total public folder quota remain unchanged. These and other limits are documented in Public Folder Limits article.

Comments (22)
  1. Nino Bilic says:

    @ericwa: Generally speaking, we recommend that you run the latest when available. Additionally, if the PF migration is over 10,000 folders then you definitely need CU6.

  2. Anonymous says:

    Good news!
    Can we expect greather data copy rates during migration process? When Public Folders database is 400 GB and data copy rates 2-3 GB/hours, the migration would take 130-200 hours.

  3. @DmitryKH, no increase in ingestion rates in CU6, but the PF team is researching possible ways to increase this. The feedback is well heard. :)

  4. Anonymous says:

    Getting ready to flip the switch on a 2007 to CU5 PF migration. Should I install this first?

  5. Hello guys,

    I had a problem here in my environment with the installation of CU6 in Exchange Server 2013.

    Of the 10 servers that I tried to install 7 servers had the same problem, the qua displays the message "fms is not starting in Exchange Server 2013 SP1".

    Anyone here experienced this problem or could tell me how to solve this problem?

    Help Please!

  6. Anonymous says:

    Hi..
    I have already done a migration of a 120.000 public-folders to Exchange 2013 prior to this releas. (SP1). If the limit has been 10.000 (cu6 increased to 100.000), i Guess this limit isn’t hard-coded in on-premise installations..

    how can beeing above this limit impact the Exchange enviorment?

    (the migration for the 120.000 folders was done cross-forest from Exchange-2010 using Quest MIgration Manager)

  7. PrabhatNigam says:

    Great changes. Thank you.

  8. Ed (DareDevil57) says:

    Thanks guys.

  9. @Endre Igesund, going beyond 100,000 folders with CU6 has risks around folder hierarchy replication stability and client access experiences.

  10. Good good News. Thank you Exchange Team.

  11. tom says:

    Are there any plans to increase the maximum individual folder size above 10gb or the Public Folder mailbox size above 100gb?

  12. So many new fixes , thanks

  13. sam says:

    is it really tested for all the scenarios, like migration, sync of permissions during migration, access to public folders creation of secondary or primary folder , when users are connecting to one of the secondary mailbox ?

  14. Qayoum says:

    Thanks for the update… Hoping for issues related with Public Folders migrating from legacy exchange servers to exchange 2013 would be fixed.

  15. AR says:

    Great one

  16. George says:

    What about native cross-forest migration, is it on the road map for Public Folders ?

  17. Bella says:

    What about accessing public folders from OWA? Still not able to do that?

  18. Aaron A says:

    Getting close, but still not ready to handle my 180,000 public folders.

  19. KEC says:

    Q: Is there a limit for the number of sub-folders within a single public folder?
    A: The recommended maximum number of sub-folders is 1000. This is the level that has been validated and is the same limit used in Exchange Online.

    Q: Is there a limit for the folder depth of the hierarchy?
    A: The recommended maximum depth of the hierarchy is 300 folder levels. This is the level that has been validated and is the same limit used in Exchange Online.

    If you maxed out each you would be at 300,000 folders or 3x past the currently supported number of folders.

    While I recognize that it is highly unlikely to max out each IMHO until the disparity between the total maximum guidance above and the total maximum number of folders supported correlate the architecture and/or guidance is illogical.

    Thank you.

  20. Bormasina says:

    Why is it so difficult to get a support for Exchange Online. I’m circling the "http://products.office.com/en-us/exchange/microsoft-exchange-features-email-for-business"
    and support nowhere to be spotted. No how-to, no tutorials, nothing. Why Microsoft is in such disarray?

  21. Phil says:

    Is there a way to get tracking logs or delivery reports on mail public folders?

Comments are closed.