When you configure journaling in an Exchange organization you should also review the configuration of any databases that will be hosting journal mailboxes. Depending on the size of your organization and the way that you deploy journaling, there is potentially a very high volume of email messages that will be stored in the journal mailbox.
In some customer environments that I’ve dealt with there have been problems encountered such as:
- High volume of journal messages causes performance problems for the database
- Transaction logging for the database hosting the journal mailbox is much higher than other databases
- The content index for the database hosting the journal mailbox is constantly crawling, or regularly fails
I usually recommend the following practices for databases that will be hosting journal mailboxes:
- Host the journal mailbox on a dedicated database.
- Configure a larger transaction log volume for the database. In a properly sized environment this shouldn’t be necessary, but some customers like to run smaller t-log volumes, which is their choice to make, but they should consider an exception in this case.
- Enable circular logging only if the the database is hosted in a database availability group and has at least two copies. If the database has a single copy only, I do not recommend circular logging due to the risk of data loss if a storage volume fails. If transaction logging creates a risk of running out of free disk space on the t-log volume, and the volume can’t be made larger as recommended above, then I recommend running frequent incremental backups of the database throughout the day (usually 2-3 backups is all that is required, but your mileage may vary).
- Disable content indexing on the database.