Considerations when deploying public folders

Applies to: Exchange Server 2013

Although there are many advantages to using Exchange 2013 public folders, you need to consider some things before you implement them in your organization.

Deployment considerations for public folders

This article contains factors to consider before you deploy public folders in your organization, especially if you plan to have a large number of public folders. Exchange 2013 now supports up to 1,000,000 public folders.

• Activity in a public folder directly impacts the load that's placed on the public folder mailbox where the folder is located. To avoid client connectivity issues, such as high latency or the inability to access a public folder, we recommend you do the following steps:

  • Don't let public folder mailboxes exceed 50% of the mailbox size limit. If this condition occurs, consider using the Split-PublicFolderMailbox.ps1 script located in the $env:ExchangeInstallPath\Scripts folder on the Exchange 2013 server to move some public folders to a new public folder mailbox.

  • Consider moving heavily used public folders to a dedicated public folder mailbox.

  • Exclude heavily used public folders from serving public folder hierarchy. You can do this action by setting the IsExcludedFromServingHierarchy property on the public folder mailbox using the Set-Mailbox cmdlet.

  • For large organizations with many public folders, consider adding additional public folder mailboxes to distribute the load of servicing public folder hierarchy requests.

• Place the primary public folder mailbox in a DAG to improve availability of the mailbox. The primary public folder mailbox is the authoritative copy of the public folder hierarchy.

• Place secondary public folder mailboxes in a DAG or back up the mailboxes frequently.

• Place public folder mailboxes in the geographical location that's nearest the users that will access the public folder content in them.

• Improve public folder hierarchy access times by using the DefaultPublicFolderMailbox property on the users' mailboxes to specify a public folder mailbox close to them. This action will prevent those users from retrieving the public folder hierarchy from a public folder mailbox in other geographical locations.

• In deployments with more than 50 secondary public folder mailboxes, we recommend that you don't store public folder content in the primary public folder mailbox. This recommendation dedicates the primary public folder mailbox to synchronizing the hierarchy with the secondary public folder mailboxes.

• Exchange 2013 no longer supports public folder databases. Therefore, Outlook Web App users with Exchange 2013 mailboxes won't be able to access Exchange 2010 or Exchange 2007 public folders. Exchange 2013 users can access Exchange 2010 or Exchange 2007 public folders with Outlook or Outlook for Mac.

• Outlook Web App is supported, but with limitations. For example, you can:

  • Add and remove favorite public folders.
  • Do item-level operations. For example, create, edit, delete, and reply to posts.

  But you can't create or delete public folders from Outlook Web App. Also, only Mail, Post, Calendar, and Contact public folders can be added to the Favorites list in Outlook Web App.

• Although a full text search of public folder content is available, you can't search for content across public folders and the content isn't indexed by Exchange Search.

• You must use Outlook 2007 or later to access public folders on Exchange 2013 servers.

• Retention policies aren't supported for public folder mailboxes.