Posey's Tips & Tricks

Best Practices for Exchange Archiving

Using carefully configured archive mailboxes can help youwork around Exchange storage limits and corporate retention policies.

Despite what your users might think, you're not limiting the size of their mailboxes as a form of punishment. Most users want to be able to keep all their e-mail messages indefinitely. On the other hand, Exchange Server has to place a practical limit on the size of each mailbox. This often creates conflicts.

There are important reasons for limiting mailbox sizes. For one thing, you have to keep the mailbox databases from growing beyond a reasonable limit. Database size has a direct impact on your ability to efficiently perform backup, restoration and other database maintenance tasks.

You also have to consider the cost of data storage. Exchange Server 2010 uses a database architecture specifically designed to decrease database I/O so you can use commodity storage hardware. Exchange Server 2013 further decreases database I/O requirements, thus making commodity storage even more practical. Even so, all storage comes at a price. When managing Exchange Server, you're often reluctant to trade high-performance storage for commodity storage for fear of performance or reliability issues.

The traditional solution has been to implement mailbox quotas as a way to limit the amount of mail users can store in their mailboxes. The trouble with this approach is that there are often legitimate business reasons why a certain user might need to store more mail than the quota allows.

That same basic problem also comes into play if you establish mail expiration policies. Some users might need to hang on to messages for longer than the specified retention period.

To the Archives
One way to address these types of problems is by using archive mailboxes. Archive mailboxes are secondary mailboxes in which users can store messages they need to keep for a longer duration. From an administrative point of view, using archive mailboxes solves several problems.

For one thing, archive mailboxes tend to be relatively static. Your users might occasionally move messages into an archive mailbox (or messages might be automatically moved through policies), but archive mailboxes certainly aren't the primary mechanism for sending and receiving mail.

As such, archive mailboxes tend to produce a much lower disk I/O load than production mailboxes. This low overhead means you can usually get away with storing archive mailboxes on low-cost, high-capacity storage without having to worry about the performance impact.

As is the case with any other type of mailbox, archive mailboxes reside in a mailbox database. Althogh the archive mailboxes can reside in the same database as the user's primary mailboxes, archive mailboxes are usually stored in a separate database so that the archived messages don't consume space on your primary storage. Keep in mind, though, that archiving is considered to be a premium feature in Exchange Server 2013. That being the case, you'll need Enterprise Client Access Licenses (CALs) for your users.

Create an Archive Database
There's really no such thing as an archive database in Exchange Server. Archive mailboxes reside in a typical mailbox database. If you plan to keep archives separate from your users' primary mailboxes, the first thing you'll need to do is to create a mailbox database dedicated to storing archive mailboxes.

You can create a mailbox database in Exchange Server 2013 by opening the Exchange Administration Center. Once that's open, click on the Servers tab and then click on the Databases link at the top of the window. When you do, Exchange will display a list of the current databases.

To create a new mailbox database, click the plus sign icon. This will cause Exchange to display the new database dialog box. You don't have to worry about specifying a database type. In Exchange 2013, there's no option to create anything but a mailbox database.

Enter a name for the database to begin creating the database. You should use a descriptive name that conveys the purpose of the database. Next, click the browse button and specify the name of the Exchange Server on which the database should reside.

You can create the database on a database availability group (DAG) member so you can replicate it to other Exchange servers in your organization. Archives are often stored on mailbox servers that aren't DAG members to avoid filling expensive storage with archive data.

The next step is to provide a database file path and a path for the transaction logs. Although Exchange will attempt to place both the database and the transaction logs on the C: drive, you should have the database and transaction logs stored on separate disks. If the disk with the database ever fails and you have to restore a backup, you can use the transaction logs to bring the database back to a current state. When you're done specifying the path, click save to create the database.

Create Archive Mailboxes
Creating the database is just the first step. The next step is to enable archiving. To do so, click on the Recipients tab. Then click on Mailboxes at the top of the console. Now, select the mailbox for which you want to enable archiving. When you do, the pane to the right of the mailbox list will display a list of mailbox features. Locate the Compliance section and click Enable.

Exchange will now display the create archive storage dialog box. Click the browse button and select the database in which you want to store the user's archive mailbox. Click ok to create the archive mailbox.

Multiple Archives
In most cases, you'll probably want to create archive mailboxes for more than one user. Creating archive mailboxes one at a time is certainly not efficient. You can script the process of creating multiple archive mailboxes through Windows PowerShell. If you aren't wild about using Windows PowerShell, there's another way to create multiple archive mailboxes with the Exchange Administration Center.

The process is almost identical to the steps I just described, except you select multiple recipients instead of a single recipient. The Compliance section still exists, but to access it you'll have to scroll to the bottom of the list and click on More Options.

When you create an archive mailbox for a user, that mailbox appears in Outlook or in Outlook Web App as a personal archive. The user can then click on the personal archive to view archived messages. The user can also manually drag messages from his inbox to the personal archive.

The whole idea behind creating personal archive mailboxes is to avoid the constraints of mailbox quotas. Even so, the archive mailboxes are stored in a typical mailbox database. Exchange Server 2013 imposes limits on mailbox databases by default. To modify the database limits, select the database containing the archive mailboxes and click the Edit icon and then select Limits. Then you can manually configure the database limits.

Automated Archival
You can use these techniques to provide users with an archival mailbox they can use to store items they wish to keep. However, it's up to your users to move important messages from the inbox to their personal archive. In some organizations, it might be effective to automate the archival process. You can do this by using Messaging Records Management.

Messaging Records Management works by assigning a series of retention policy tags to default folders such as the inbox. Typically, you'll have to apply a default policy tag to the mailbox used to manage the retention for any item not manually tagged. However, the user can assign personal tags to individual items he wishes to retain.

You can think of retention tags as a series of policy elements controlling the way data is retained. A retention policy is a collection of retention policy tags. Once you've applied a retention policy to a mailbox, the Managed Folder Assistant periodically analyzes the contents of the mailbox and processes messages according to the retention policy you've applied. You can learn more about deploying retention policies on the TechNet Library page, "Checklist: Deploying Retention Policies."

User job requirements are often at odds with IT department policies when it comes to message retention. Archive mailboxes are an effective solution for you to provide your users with long-term storage capabilities, without impacting your Exchange infrastructure's primary storage.

About the Author

Brien Posey is a 22-time Microsoft MVP with decades of IT experience. As a freelance writer, Posey has written thousands of articles and contributed to several dozen books on a wide variety of IT topics. Prior to going freelance, Posey was a CIO for a national chain of hospitals and health care facilities. He has also served as a network administrator for some of the country's largest insurance companies and for the Department of Defense at Fort Knox. In addition to his continued work in IT, Posey has spent the last several years actively training as a commercial scientist-astronaut candidate in preparation to fly on a mission to study polar mesospheric clouds from space. You can follow his spaceflight training on his Web site.


comments powered by Disqus

Subscribe on YouTube