Check the last transaction log file that was written into the Exchange database.

The Exchange store uses write-ahead transaction logs and checkpoint files to help prevent data loss. Transaction logs record all the changes that have been committed to the in-memory database, while checkpoint files record which logged transactions have been written to the on-disk database files.

To check the last log file that has been written to the on-disk database, you can run the following in Exchange PowerShell. It will  provide the Checkpoint file that was last committed.  Any log files after that checkpoint file have not been committed to the on-disk database yet, where any log files prior have already been written and can be safely removed if manual purge is required.

Powershell:  ESEUTIL /MK E:\Database\Logs\E00.chk

Extensible Storage Engine Utilities for Microsoft(R) Exchange Server
Version 14.03
Copyright (C) Microsoft Corporation. All Rights Reserved.

Initiating FILE DUMP mode...
      Checkpoint file: E:\Database\logs\E00.chk

      LastFullBackupCheckpoint: (0x0,0,0)
      Checkpoint: (0x4E1617,80,0)      <-- The log file may look like E00004E1617.log in the logs directory.
      FullBackup: (0x4D48C3,173,1E1)
      FullBackup time: 05/18/2014 06:01:36
      IncBackup: (0x4E0CB3,447,48)
      IncBackup time: 05/23/2014 05:04:41
      Signature: Create time:06/05/2012 15:17:03 Rand:89681821 Computer:
      Env (CircLog,Session,Opentbl,VerPage,Cursors,LogBufs,LogFile,Buffers)
          (    off,   2027, 101350,  16384, 101350,   2048,   2048,1804596)

Operation completed successfully in 0.32 seconds.