Microsoft Exchange Server 2016: Public Folders
In this tutorial we are going to learn about public folders and how they work in Exchange 2016.
Public folders are made and designed for shared access and offer an easy and effective way to collect, organize, and share concerned information with other people present in your workgroup or organization. Public folders help and support make content in a deep hierarchy simpler and easier to browse. Users will observe the full hierarchy in Outlook, that makes it easy for them to search the content they’re interested in.
Public folders are present in the following Outlook clients: Outlook available over the web for Exchange 2016, Outlook 2007 or later, and Outlook for Mac.
Public folders might also be used as an archiving strategy for distribution groups. While you mail-enable a public folder and append it as a member of the distribution group, email transmitted over to the group is automatically appended over to the public folder for later reference.
You should use Outlook 2007 or later versions to access public folders over the Exchange 2016 servers.
Public folders aren’t made and designed to perform the following:
- Data archiving Users who consist of mailbox limits sometimes use public folders instead of mailboxes to archive data. Such practice isn’t suggested as it affects storage in public folders and undermines the objective of mailbox limits. Rather, we suggest that you use In-Place Archiving in Exchange 2016 as your archiving solution.
- Document sharing and collaboration Public folders don’t offer versioning or other document management features, like controlled check-in and check-out functionality and automatic notifications of content changes. Rather, we recommend that you use SharePoint as your documentation sharing solution.
- Public folder architecture
- Migrate public folders from previous versions
- Public folder moves
- Public folder quotas
- Disaster recovery
Public folder architecture
- In Exchange 2016, public folders use a mailbox infrastructure to take benefit of the existing high availability and storage technologies of the mailbox database. Public folder architecture uses particularly designed mailboxes to save and store both the public folder hierarchy and the content. This also implies that there’s no longer exists a public folder database as there was in earlier version of Exchange. High availability for the public folder mailboxes is offered by a database availability group (DAG).
- The major architectural components of public folders are the public folder mailboxes, that can reside in one or more mailbox databases.
Public folder mailboxes
There are two kinds of public folder mailboxes: the primary hierarchy mailbox and secondary hierarchy mailboxes. Both categories of mailboxes might contain content:
- Primary hierarchy mailbox The primary hierarchy mailbox is the kind of writable copy of the public folder hierarchy. The public folder hierarchy is replicated and copied to all other public folder mailboxes, however, these will be read-only copies.
- Secondary hierarchy mailboxes Secondary hierarchy mailboxes includes public folder content as well and a read-only replica of the public folder hierarchy.
Retention policies are not supported for public folder mailboxes.
There are two methods you can manage public folder mailboxes:
- In the Exchange admin center (EAC), navigate and traverse on Public folders > Public folder mailboxes.
- In the Exchange Management Shell, use the *-Mailbox set of cmdlets. The following parameters have been appended to the New-Mailboxcmdlet to help and support public folder mailboxes:
- PublicFolder This given parameter is usually used with the New-Mailbox cmdlet to build or create a public folder mailbox. When you build a public folder mailbox, a new mailbox is created along with the mailbox type of PublicFolder.
- HoldForMigration This parameter is generally used only if you are migrating public folders from a earlier version to Exchange 2016.
- IsHierarchyReady This parameter depicts whether the public folder mailbox is suitably ready to serve the public folder hierarchy to users. Its fix to set to $True only after the whole hierarchy has been synced to the public folder mailbox. In case the parameter is set to $False, users won’t use it to access the hierarchy.
- But, if you set the DefaultPublicFolderMailbox property on a user mailbox to a particular public folder mailbox, the user will still access the mentioned public folder mailbox even if the IsHierarchyReady parameter is set to$False.
- IsExcludedFromServingHierarchy This parameter restrains users from accessing the public folder hierarchy on the mentioned public folder mailbox. For load-balancing purposes, usually users are equally distributed across public folder mailboxes by default. And when this parameter is set on a public folder mailbox, that respective mailbox isn’t included in this automatic load balancing and won’t be viewed or accessed by users to retrieve the public folder hierarchy.
- But, if you set the DefaultPublicFolderMailbox property on a user mailbox to a particular public folder mailbox, the user is going to still access the specified public folder mailbox even in case the IsExcludedFromServingHierarchyparameter is set for that public folder mailbox.
A secondary hierarchy mailbox is going to serve only public folder hierarchy information to users if it’s mentioned explicitly on the users’ mailboxes using the DefaultPublicFolderMailbox property, or In case the following conditions are met:
- The IsHierarchyReady property present on the public folder mailbox is set to $True.
- The IsExcludedFromServingHierarchy property present on the public folder mailbox is set to $False.
Public folder hierarchy
The public folder hierarchy includes the folders’ properties and organizational information, inclusive of tree structure. Every public folder mailbox includes a copy of the public folder hierarchy. There’s only single writeable copy of the hierarchy that is in the primary public folder mailbox.
For a particular folder, the hierarchy information is used to determine the following:
- Permissions present on the folder
- The folder’s position in the public folder tree, consisting of its parent and child folders.
The hierarchy doesn’t save or store information about email addresses for mail-enabled public folders. The email addresses are saved and stored on the directory object in Active Directory.
- The public folder hierarchy synchronization process mainly utilizes Incremental Change Synchronization (ICS) that provides a mechanism to track, monitor and synchronize alterations to an Exchange store hierarchy or content. The changes consist of creating, deleting and modifying folders and messages.
- In the case when users are connected to and using content mailboxes, synchronization happens in every 15 minutes. In case no users are connected to content mailbox, synchronization is going to be triggered less often (in every 24 hours).In case a write operation like a creating a folder is performed over the primary hierarchy, synchronization is triggered instantly (synchronously) to the content mailbox.
As there’s only single writeable copy of the hierarchy, folder creation is usually proxied to the hierarchy mailbox by the content mailbox users are connected to.
- In a big organization, while you create a new public folder mailbox, the hierarchy should synchronize to that public folder before the end-users can connect to it. Else, users may see an incomplete public folder structure while connecting with Outlook.
- To permit time for this synchronization to happen without users attempting to connect to the new public folder mailbox, set the IsExcludedFromServingHierarchyparameter on the New-Mailbox cmdlet when building or creating the public folder mailbox. Such parameter prevents users from connecting to the newly created public folder mailbox.
- When synchronization is complete, run the Set-Mailbox cmdlet with the IsExcludedFromServingHierarchyparameter set to false, depicting that the public folder mailbox is instant ready to be connected to. You might also use the Get-PublicFolderMailboxDiagnostics cmdlet to access the sync status by the SyncInfo and the AssistantInfo properties.
Public folder content
Public folder content may include email messages, documents, posts, and eForms. The content is saved and stored in the public folder mailbox however isn’t replicated across multiple public folders mailboxes. All users view and access the same public folder mailbox for the same set of content. Though a full text search of public folder content is present, public folder content isn’t searchable across public folders and the content is not indexed by Exchange Search.
Outlook over the web is supported, however with limitations. You may add and delete public folders to your Favorites through Outlook, and then conduct item-level operations such as creating, deleting posts, editing, and replying to posts via Outlook on the web. But, you can’t create or delete public folders from Outlook on the web. Further only Mail, Post, Calendar, and Contact public folders can be added to the Favorites list in Outlook on the web.
Migrate public folders from earlier versions
- In case you are already equipped with Exchange 2010 SP3 public folders in your organization prior to installing Exchange 2016, you should migrate those public folders to Exchange 2016. To perform this, use the PublicFolderMigrationRequst cmdlets.
- In case your organization is shifting to Exchange Online, you can move your public folders to the cloud and upgrade them at the same time.Because of the changes present in how public folders are stored, legacy Exchange mailboxes are unable to access the public folder hierarchy on Exchange 2013 or Exchange 2016 servers or on Exchange Online. But, user mailboxes on Exchange 2016 servers can connect to legacy public folders.
- Exchange 2016 public folders and legacy public folders cannot present in your Exchange enterprise simultaneously. This effectively depicts that there’s no coexistence among versions. Migrating public folders to Exchange Server 2016 or Exchange Online is presently a one-time cutover process.Therefore, it’s recommended that prior to shifting your public folders, you must first migrate your legacy mailboxes over to Exchange 2016 or Exchange Online.
Public folder migrations or moves
- You are allowed to move public folders to a different public folder mailbox, and you are allowed to move public folder mailboxes to distinguished mailbox databases. To shift public folders to different public folder mailboxes, use the PublicFolderMoveRequest set of cmdlets.
- Subfolders under the public folder which is being shifted won’t be moved by default.
- In case you wish to move a branch of public folders, you can utilize the Move-PublicFolderBranch.ps1 script which is installed by default with Exchange 2016.Further, in addition to moving public folders, you can also shift public folder mailboxes to different mailbox databases by using the MoveRequest set of cmdlets.
- This is the same set of cmdlets which are used for migrating regular mailboxes.To migrate public folders asynchronously, PublicFolderMoveRequest cmdlets and the MoveRequest cmdlets use the Mailbox Replication Service. That implies that the cmdlet doesn’t do the actual work and, while making most of the move, the public folder and public folder mailboxes will still be available to users.
- As the Mailbox Replication Service conducts mailbox moves, import and export requests, and public folder shift or move requests, it’s imperative to consider throttling and workload management.
Public folder quotas
When public folders are created, public folder mailboxes automatically by default inherit the size limits of the mailbox database defaults.
- Consequently, to correctly analyze and evaluate the current storage quota status when using the Get-Mailbox cmdlet, you should review and re-analyze at the UseDatabaseQuotaDefaults property in addition to theProhibitSendQuota, ProhibitSendReceiveQuota, and IssueWarningQuota properties.
- In case the UseDatabaseQuotaDefaults property is set to true, the per-mailbox settings are ignored and the mailbox database restrictions are used.In case this property is set to true and the ProhibitSendQuota,ProhibitSendReceiveQuota, and IssueWarningQuota properties are fix and set to unlimited, the mailbox size isn’t really unlimited.
Instead, you should use theGet-MailboxDatabase cmdlet and review the mailbox database storage capacity or limits to find out what the limits for the mailbox are. In case theUseDatabaseQuotaDefaults property is set to false, the per-mailbox settings are then used. In Exchange 2016, the default mailbox database quota restriction limits are as follows:
- Issue warning quota: 1.9 GB
- Prohibit send quota: 2 GB
- Prohibit receive quota: 2.3 GB
Exchange Server 2016 public folders are created and developed on mailbox infrastructure and use the same mechanisms for availability and redundancy. Each public folder mailbox might have multiple redundant copies with default automatic failover, just like regular routine mailboxes.
Moreover, In addition to the overall disaster recovery scenario, you might also restore public folders in the following situations:
- Soft-deleted public folder restore The public folder was removed but is still within the retention period.
- Soft-deleted public folder mailbox restore The public folder mailbox was removed and is still within the mailbox retention period.
- Public folder mailbox restore from a recovery database You may recover an individual public folder mailbox from backup while the deleted mailbox retention period has elapsed. Then you are allowed to extract data from the restored mailbox and replicate it to a target folder or then merge it with another mailbox.
In all above mentioned situations, the public folder or public folder mailbox is recoverable by using MailboxRestoreRequest cmdlets.