Exchange 2007 - Clear Transaction Logs

• Run NTBackup and start an incremental backup on the affected storage group immediately 
  • Check the amount of space remaining and how quickly the drive is filling up. If it looks like NTBackup won't be able to complete before the drive fills up (the DB's will dismount) then proceed to performing the step below. 
• On the Active mailbox server, run the following command in Powershell - make sure to update the path below accordingly 
  • eseutil /MK "H:\database\Third Storage Group\E02.chk"
  • The output will have a Checkpoint entry that looks like this:
    Checkpoint: (0x35B88,80,0)
  • 35B88 is the last 5 characters of the last transaction log that is needed by the DB. So if there are logs older than this file (35B87, 35B86, etc...) then those logs have been committed by the Database and are no longer needed. Ensure that you sort the view in Explorer by modified, since sorting by Name will not sort them properly.
  • You can proceed to move those logs elsewhere to free up the space, and then run an Incremental Backup to purge the remaining logs.