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Understanding Exchange Online Archiving


Applies to: Exchange Server 2010 SP3, Exchange Server 2010 SP2

Microsoft Exchange Online Archiving is a cloud-based, enterprise-class archiving solution for your Exchange Server 2010 Service Pack 1 (SP1) or later on-premises organization. With Exchange Online Archiving, your organization can host your users’ primary mailboxes on your on-premises servers and store their historical e-mail data in cloud-based archive mailboxes. This solution can assist your organization with archiving, compliance, regulatory, and e-discovery challenges, while simplifying your on-premises infrastructure. EOA provides you the following advantages:

Help meet long-term retention requirements Cloud-based archives allow you to store large quantities of messaging data off-site in secure and controlled datacenters. Exchange Online Archiving helps your organization meet regulatory compliance or business requirements for long-term retention of e-mail. Using archive policies, messages are moved from on-premises mailboxes to the cloud-based archives. The same retention policies applied to on-premises mailboxes can be enforced on cloud-based archives.

Help meet eDiscovery and litigation hold requirements With cloud-based archives for your on-premises mailbox users, you can perform seamless discovery searches across both the on-premises primary mailbox and the cloud-based archive. When users are placed on litigation hold in your on-premises organization, their cloud-based archive is also placed on hold.

Lower storage costs Moving historical e-mail data to a cloud-based archive allows you to reduce your organization’s storage requirements. You can provision users’ primary mailboxes with appropriate mailbox quotas, which keeps mailbox sizes in control and your storage costs low.

Provide Anywhere Access Cloud-based archive mailboxes are similar to an on-premises archive mailbox. Using Outlook 2010, Outlook 2007 or Outlook Web App, users are able to access older messages and content in the archive transparently, without requiring any additional configuration on their computers.

> [!NOTE]
> Outlook users can access an archive mailbox in online mode. Archive mailboxes aren’t cached to the user's computer when using Outlook in Cached Exchange Mode.

To learn about the various archiving terms used in Exchange 2010, see Archiving Terminology in Exchange 2010.

Exchange Online Archiving Requirements and Setup

The following are general requirements required to configure Exchange Online Archiving.

  • You must purchase an Exchange Online Archiving subscription for the Exchange Online service included with Office 365. For more information, see Exchange Online Archiving subscription.

  • User’s primary mailboxes must be hosted on on-premises Exchange 2010 SP1 or later Mailbox servers.

  • You must configure a subset of steps required for a hybrid deployment between your on-premises organization and Office 365. Details are described in Configure Exchange Online Archiving.

  • Users must use Outlook 2010, Outlook 2007 SP2, or Outlook Web App to access the cloud-based archive mailbox.

  • To use Office 2010 or Office 2007 with Exchange Online Archiving, you must configure your users' computers to support Office 365. For more information, see Manually update and configure desktops for Office 365.

To set up Exchange Online Archiving, you must perform a subset of steps required for a hybrid deployment for Exchange Online. If your on-premises organization has been upgraded to Exchange 2010 SP2, you can use the Hybrid Configuration Wizard to perform this setup. Additionally, you can configure single sign-on, which is based on Active Directory Federation Services (AD FS). This allows your users to access on-premises mailboxes and cloud-based archives with a single username and password..


Although you can configure Exchange Online Archiving without setting up single sign-on using AD FS, we highly recommend that you configure single sign-on. Doing so helps to avoid additional authentication prompts when users try to access their cloud-based archive.
If you deploy a configuration without AD FS, access to the cloud-based archive using Microsoft Outlook is supported only when the user’s UPN in your on-premises and cloud-based organizations matches and both use the same password. In this case, Microsoft Outlook users will be prompted for credentials when accessing the cloud-based archive for the first time. When entering credentials, users can select the Save password option to avoid subsequent authentication prompts.

For complete instructions about how to set up Exchange Online Archiving for you organization, see Configure Exchange Online Archiving

Managing Exchange Online Archiving

Managing cloud-based archives is similar to managing personal (on-premises) archives. You can use the Exchange Management Console (EMC) or the Exchange Management Shell to perform the following tasks:

Moving Data to a Cloud-Based Archive

You can use retention policies to move messages to a user’s cloud-based archive. When you enable an archive, the default retention policy called Default Archive and Retention Policy is automatically applied to the user. This policy has a default policy tag (DPT) assigned that moves items to the archive mailbox after two years. You can also create your own archive and retention policies and apply them to mailbox users. To learn more about archive policies, see Understanding Personal Archives. To learn more about retention tags and retention policies, see Understanding Retention Tags and Retention Policies.

Users can also move messages to their archive by using the following methods:

  1. Apply archive policies to individual messages or folders. Archive policies are implemented by creating personal tags that use the Move to Archive action. For details about how to create retention tags, see Create a Retention Tag.

  2. Use Inbox rules to either move messages to a folder that has an archive policy assigned or have the rule apply an archive policy to the message itself. To learn more about Inbox rules, see Manage email messages by using rules.

  3. Move messages manually in Outlook or Outlook Web App.

For all these operations, the cloud-based archive behavior is similar to a personal archive.

Exporting Data From a Cloud-Based Archive

Users can move messages from their cloud-based archive to their primary mailbox by using Outlook or Outlook Web App. Users can also move or export messages to a .pst file by using Outlook. For details, see Export Multi-Mailbox Search Results to an Outlook Data File (.pst).


To protect your organization’s messaging data, you can disable users’ ability to move messages from their primary mailbox or cloud-based archive to a .pst file or another mailbox. To do this, use Registry entries or the group policy settings included in the Office 2010 Administrative Templates. For details, see Plan for compliance and archiving in Outlook 2010.

You can also export a cloud-based archive to a .pst file by first moving it to an on-premises Mailbox server and then creating a mailbox export request. To learn more about export requests, see Understanding Mailbox Import and Export Requests.

Cloud-Based Archives and Retention

Archive policies, which you create on an on-premises Mailbox server, move messages to the user’s personal or cloud-based archive. Once in the archive, messages must continue to be processed and removed based on the user’s retention policy.

To accomplish this, you must export retention policies and retention tags from your on-premises organization and import them to your cloud-based organization in Exchange Online. After you complete the import process, the imported policies are applied to cloud-based archive mailboxes, and messages expire based on users’ retention policies.


If you make changes to retention tags or retention policies in your on-premises organization (for example, if you create a new retention tag, modify the retention age property of an existing tag, or remove a tag), you must perform the export and import procedure again to make sure that the retention tags and policies from your on-premises organization are also updated in Exchange Online.

Cloud-Based Archives, Discovery, and Litigation Hold

In Exchange 2010, you can use Multi-Mailbox Search to perform discovery searches in mailboxes across your organization. When performing a discovery search, users’ cloud-based archives are also searched. No additional action is required to include a cloud-based archive in the search. Messages returned in a search are copied to the on-premises discovery mailbox specified in the search. To learn more about discovery searches, see Understanding Multi-Mailbox Search.

Similarly, when a mailbox user is placed on litigation hold, the user’s cloud-based archive is also placed on hold. Messages aren’t purged from the cloud-based archive until the hold is removed. To learn more about litigation hold, see Understanding Litigation Hold.

Cloud-Based Archives and Auditing

The following auditing features in Exchange 2010 also work with Exchange Online Archiving:

Mailbox audit logging   In Exchange 2010 SP1 and later, you can enable mailbox audit logging to log access by delegate users or administrators and the mailbox owner. When mailbox audit logging is enabled for a mailbox, the configured settings are also applied to the user’s cloud-based archive. The same on-premises tools used to retrieve audit log entries for the on-premises mailbox also return mailbox audit entries for the cloud-based archive. To learn more, see Understanding Mailbox Audit Logging.

Administrator audit logging   In Exchange 2010 SP1 and later, administrator audit logging allows you to audit actions taken administrators when they use the EMC, Exchange Control Panel (ECP), or the Shell to make a change in your organization. If admin audit logging is enabled on your on-premises server, all administrative operations performed against Exchange Online Archiving are also logged. You must search the administrator audit logs in your on-premises Exchange organization separately from the Exchange Online Archiving audit logs. To learn more, see Overview of Administrator Audit Logging.

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