Exchange如果不采用循环日志，在成功实现全备份前，将产生大量DB日志。当磁盘性能比较差时，Exchange将延缓日志提交到数据库。因此这部分日志绝对不能删除，否则DB会有问题。而那些已经提交的db的log，其实可以手工delete掉（普通删除文件的方法）。当备份出现问题，磁盘容量又不够时，该方法非常有用。

以下KB就是帮助用户如何确定哪些日志已经提交，可以删除。

XADM: Using Eseutil to Determine Which Logs Have Been Committed
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Article ID : 182961 
Last Review : October 28, 2006 
Revision : 4.3 
This article was previously published under Q182961
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SUMMARY

MORE INFORMATION

Exchange Server 5.5

Exchange 2000 Server
SUMMARY
You can use the Eseutil utility to view the contents of the checkpoint file to determine which log files have been committed to an Exchange database. 
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MORE INFORMATION
Exchange Server 5.5
The information in this section applies to all three Exchange Server 5.5 databases: • Dir.edb 
• Priv.edb 
• Pub.edb 
To display the Edb.chk (checkpoint) file on the screen, run the following command from a command prompt: 
eseutil /mk edb.chk | more
If you do not run eseutil from the folder where the Edb.chk file is located, you must provide the full path to the file.

In Exchange Server 5.5, there is one checkpoint file for each set of log files. There will be one Edb.chk file for the directory and one for the information store. (Priv.edb and Pub.edb share the same log files and checkpoint file.) 

The information that is displayed is similar to:    Microsoft(R) Exchange Server Database Utilities

   Version 5.5

   Copyright (C) Microsoft Corporation 1991-1997. All Rights Reserved.



   Initiating FILE DUMP mode...
      Checkpoint file: edb.chk

      LastFullBackupCheckpoint (8,615,203)
      Checkpoint (22,6485,399)
      FullBackup (8,615,203)
      FullBackup time:3/6/1998 11:52:16
      IncBackup (0,0,0)
      IncBackup time:0/0/1900 0:0:0
      Signature: Create time:2/24/1998 14:23:47 Rand:24842 Computer:
      Env (Session, Opentbl, VerPage, Cursors, LogBufs, LogFile, Buffers)
          (    168,   25200,    4440,    8400,      84,   10240,    8045)

   Operation completed successfully in 0.20 seconds.
                                
Take the first number in the parentheses for the Checkpoint field and convert it to hexadecimal. The hexadecimal number is the file name of the first uncommitted log for the appropriate directory. Circular logging works by deleting all log files with generations that are lower than the generation in the checkpoint, for example: 
Checkpoint (22,6485,399) = EDB00016.LOG 
This syntax applies for most other fields in the dump file (LastFullBackupCheckpoint, FullBackup, IncBackup, and other fields). 
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Exchange 2000 Server
In Exchange 2000, there is one checkpoint file for each storage group and one for the directory. When you try to identify the last committed log file for a storage group, note that the storage group prefix applies to the checkpoint file and to all of the log files. For example, the default first storage groups checkpoint file name is E00.chk, and its log files are E00xxxxxx.log (where xxxxx is the hexadecimal sequence number of the log file).

To display the Exx.chk (checkpoint) file on the screen, run the following command from a command prompt (from the Exchsrvr\Bin folder): 
eseutil /mk the_full_path_to_the_checkpoint_file
For example, you may run the following command: 
eseutil /mk "C:\Program Files\Exchsrvr\MDBDATA\E00.chk"
Note that you must use the quotation marks if there is a space in the path to the checkpoint file.

The output of this command is similar to:    Microsoft(R) Exchange Server(TM) Database Utilities
   Version 6.0
   Copyright (C) Microsoft Corporation 1991-2000.  All Rights Reserved.

   Initiating FILE DUMP mode...
         Checkpoint file: C:\Program Files\Exchsrvr\MDBDATA\E00.chk

         LastFullBackupCheckpoint: (0x0,0,0)
         Checkpoint: (0x6A,1119,3D)
         FullBackup: (0x0,0,0)
         FullBackup time: 00/00/1900 00:00:00
         IncBackup: (0x0,0,0)
         IncBackup time: 00/00/1900 00:00:00
         Signature: Create time:09/24/2001 17:10:26 Rand:522553071 Computer:
         Env (CircLog,Session,Opentbl,VerPage,Cursors,LogBufs,LogFile,Buffers)
             (    off,    202,  30300,   1365,  10100,    128,  10240,  97940)

   Operation completed successfully in 1.192 seconds.
                                
Take the first number in the parentheses for the Checkpoint field. The hexadecimal number is the file name of the first uncommitted log for the appropriate database; in this example: 
Checkpoint (0x6A,1119,3D) = E000006A.log 
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