Exchange 2010 mailbox database logs

exchange-2010log-files

We recently discovered that an Exchange Server could not accept any (external) messages anymore due to low disk space. It is the Exchange "Back Pressure" feature that caused the Exchange Server to stop sending emails.

Now using a tool I found that there are many log files (.log) in directory:

C:\Program Files\Microsoft\Exchange Server\V14\Mailbox\Mailbox Database <id>\

These log files take up several GBs and thus all my resources (disk space), causing my problem.

I had that specific directory open for a few minutes and it was updating and adding logs. To me it looks like it logs every incoming (?)/outgoing (?) email.

Questions:

  1. Is it safe to manually delete these mailbox database .log files or should this be done by an Exchange tool?
  2. How can I control this logging? (enable/disable/auto-cleanup/… settings?)
  3. What exactly does such a mailbox database .log file contain?

Thanks in advance.

Best Answer

  1. No it is not safe to simply delete log files to free space. They are critical to the functionality of Exchange.
  2. You can use an Exchange aware backup solution that can truncate the logs (delete them) once a backup is completed. Another option is to use circular logging (But will remove recoverability of data if you do not have a backup solution). This is extremely high level and you need to decide on which strategy is best for your environment.
  3. Log files track changes to a users mailbox and to ensure no loss of data in the event of a dirty shut down of a database.

In addition, you've created a mailbox in the default location. It is best practise to create a new volume for the databases and another for the log transaction files.

Good article describing the same issue you have: http://exchangeserverpro.com/exchange-2010-faq-disk-filling-log-files/

Related Topic