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Exchange Server 2016 Migration – Configuring Mailbox Databases

At this stage of the Exchange 2016 migration the Mailbox server has been installed, and the client access services have been configured. To continue with the configuration of the server, in this article we’ll look at configuring mailbox databases.

For many Exchange migrations, an organization will migrate to a database layout that is much the same as their existing layout. For example, if the organization previously had five mailbox databases, then they’ll create the same number of databases on the new server that they are migrating to. However, a migration is a good opportunity to review how many databases you need, and how you distribute your mailbox among them. For example:

  • Your mailbox sizes may have grown, requiring larger databases or more databases to host the same amount of mailbox data. Growth in mailbox data size should be accounted for in your planning and design, and included in your calculations when you used the Exchange server role requirements calculator to size your servers and storage.
  • If you’ve previously used a rigid system for assigning mailboxes to databases, you can consider changing to a more flexible, capacity-based system.
  • Public folder mailboxes need to be accounted for if you are migrating from Exchange 2010 to Exchange 2016, because public folder data is no longer stored in a separate, dedicated databases, and is now stored in public folder mailboxes in the same databases as other mailbox types.
  • If you’re migrating from a standalone Mailbox server to a database availability group, there are different maximum database sizes recommended by Microsoft, which could change the database sizes you plan to use.

For the Not Real University migration, the Exchange 2010 and Exchange 2013 servers in the organization have a single mailbox database each. The Exchange 2010 server also hosts a public folder database.

The new Exchange 2016 server will be configured with five mailbox databases, which is the maximum for a Standard Edition license of Exchange 2016, to host all of the existing mailbox and public folder data.

The Exchange 2016 server already has a single mailbox database that was created by Exchange setup. The database and log files are located in the default paths, in the same Program Files location that the Exchange application files were installed. The database also has a uniquely generated name.

Neither the default location or name are suitable for this deployment, so the first step is to rename the database to match the naming scheme used in this environment.

Next, we can move the mailbox database and log files to their intended location on the database and log volumes that have been configured on the server. This move involves an outage of the database while it is dismounted, moved, and remounted, so you should ideally perform this task before migrating any mailboxes to the database.

Next, we need to create the four additional mailbox databases.

The Information Store service should be restarted after creating the new databases, which ensures the correct memory allocation will be provided for each database. This will cause an outage for the databases on the server, so again you should perform this task before migrating any mailboxes.

Now that all the databases have been created, they need to be configured for storage quotas and the offline address book. The storage quotas for the existing databases in the environment were collected during the planning stage of the project. For Not Real University, the new mailbox databases will have a larger storage quota than the previous databases, to reflect the growing use of email by users in the organization.

For the offline address book, you can choose to leave the option blank for each database, and the mailboxes hosted on that database will use the default offline address book in the organization. Alternatively, you can assign a specific offline address book to each database.

The default OAB when Exchange 2016 is installed the OAB named “Default Offline Address Book (Ex2013)”.

Now that the databases have been configured, it is a good time to implement and test your backups. If you don’t have a backup application available, you can use use Windows Server Backup to protect your Exchange 2016 databases. Backups should be fully configured and tested before the server goes into production.

In the next article in this series, we’ll look at preparing for co-existence.

Paul is a Microsoft MVP for Office Servers and Services. He works as a consultant, writer, and trainer specializing in Office 365 and Exchange Server. Paul is a co-author of Office 365 for IT Pros and several other books, and is also a Pluralsight author.
Category: Exchange Server



    We can delete the default db which is created rather renaming and moving to new location and just create new DB in new location.

    • It’s easier to move it. There’s a system mailbox on that first database that will prevent the removal of the database unless you move the system mailbox first, so it easier to just move the database. It’s a brand new database with no data in it, only takes a few moments to move.

    • Joerg Renggli says:

      Hi all,

      Usually I install Exchange already with the correct DB name and path:

      Setup.exe /mode:Install /role:MB, CA /IAcceptExchangeServerLicenseTerms /TargetDir:”C:Program FilesMicrosoftExchange ServerV15″ /mdbname:DB01 /dbfilepath:d:DB01DB01.edb

      But of course I guess you just wanted to illustrate how to move and rename a database.

  2. Hari says:


    How to set specific mailbox database size …. i need to create 4 databases and each holding 200GB size.

    Thanks in advance

  3. Martin says:

    First off, great tutorial. We are planning on splitting up user’s mailboxes from their online archives. That way we can utilize slower less expensive disks for the online archives and faster disks for the mailboxes. I realize this complicates management a little but I’m looking to see if you have any advise concerning the auto provisioning features in 2016? Also, any advise migrating those mailboxes to a split database configuration?

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