Worried about your Exchange 2010 disk space?  One of the biggest fears an Exchange Administrator has is the disk volume containing an Exchange Database, or Exchange Transaction Logs, running out of disk space.  Usually this is due to an unplanned event.   This blog post provides a simple (free) safeguard you can implement to your Exchange environment (Exchange 2003, Exchange 2007, Exchange 2010, and maybe Exchange 2013).   The proposed Exchange 2010 disk space safeguard has saved me more than once !  It may save you one day too …

Low on Exchange 2010 Disk Space

Running out of Exchange 2010 disk space (or Exchange 2007 or Exchange 2013) can cause all mailboxes on the related Exchange Database to stop being able to send or receive email.  Or worse, the Exchange Database can become dismounted.    Typically, it is not easy to bring the Exchange Database online easily, as you need some free disk space, and quickly !   As Exchange operates with pre-allocated disk volumes, this can be a challenge !

There are two Exchange 2010 disk space scenarios covered here:

• The Exchange 2010 Database disk volume running out of space is more serious, as you will not be able to remount it without making additional disk space available.   Doing this could take some time, and configuration changes in Disk Manager. Or it may not be an option at all. Meanwhile, you have users complaining at the loss of mail service!
• If the Exchange 2010 Transaction Log disk volume runs out of space, you at least have the option to move a large number of transaction log files elsewhere temporarily.

Proposed Exchange 2010 Disk Space Solution:

My suggestion is simple, and free.   Use Microsoft Word to create a file of 1GB in size.  You can do this by pasting images into the Word document.  When the file is created of the right size, save the file with a name similar to “delete_when_you_need_diskspace.doc”

Then, place a copy of this 1GB file into the root of each disk volume that is used by your Exchange 2010 Databases, and Exchange 2010 Transaction Log files.   Of course, check you have free disk space first, as this file will use up valuable disk space on your Exchange Server .  I also assume your Exchange 2007/2010/2013 server has disk volumes sized appropriately.   You can also choose a different file size to suit your environment – for example, 500MB, or 2GB.

Once this file has been placed into the root of all appropriate Exchange Database and Transaction Log disk volumes, you have a safety valve.   If, for any reason, one of your disk volumes runs out of disk space now, you have the option of deleting the “delete_when_you_need_diskspace.doc”  file from the related disk volume, allowing you to re-mount the Exchange Database(s) affected.  Then you can look to move some mailboxes off, or do other work to fix the issue.

Note: if you use Exchange 2007 CCR/SCR or Exchange 2010 DAG, then make sure that you place the required “delete_when_you_need_diskspace.doc”  file into all disk volumes required on all servers, including cluster server nodes.   If you have an Exchange 2007 CCR environment, with SCR as well, then the above file would need to be placed onto three places for all Exchange 2007 Storage Group disk volumes.

Low Exchange 2010 Disk Space Conclusion:

The above free solution, although using up Exchange 2010 disk space, provides a simple safeguard against unplanned events affecting your Exchange 2003/2007/2010 (and maybe Exchange 2013) environment. It will not stop you running out of Exchange 2010 disk space, but it will give you the chance to recover from the situation, and stay in control.   It has saved me on more than one occasion.     If this tip helps you out, do not forget to put the safeguard file back into place after you have resolved the issue.   Send me feedback if it has helped you.