There are at least two reasons, why a regular backup of your Exchange 2010 (Mailbox) Databases is important:

  -  1. the associated log files of a database are truncated after a successful backup

  -  2. you have to be ready for a disaster (and to be able to restore your db’s)

In this post I will show you, how you can use the Server 2008 R2 built in Backup tool to create such a backup  (you need R2!) depending on VSS where the log files are truncated!