It is well
known that Exchange Server transaction logs keeps the full record of the performed
changes in the Exchange Server database, and these log files should be
periodically removed from the hard disk because these log files gather or
acquire all the available free disk space.
Usually,
the size of Exchange transaction log file is fixed, exact 5MB, for MS Exchange
Server 2003 and all earlier versions. If the particular transaction log is
full, it is renamed with a numeric sequence number and a new current log is
generated. Here the current transaction log is the most recently created by
Exchange Server.
These
transaction logs are being called from different names corresponding to MS
Exchange version. For example, In MS Exchange Server version 5.5, the current
transaction log file is called Edb.log and for Exchange Server version 2000 and
2003, the current log is named with the Storage group prefix.
There are
some in-built methods in Exchange which removes the unnecessary log files
automatically which are as follows:
When circular logging is enabled: This
method removes transaction logs after they have been removed written to the
database group.
When circular logging is disabled: This method
removes excess logs after a complete or full online backup of all the databases
in a storage group is performed.
However,
sometimes you have to manually remove the transaction log files when you
anticipate running out of hard disk. If removing a log which holds data that
hasn't been written on Exchange database file, then database databases will no
longer be mountable after an abnormal stop.
In order to
remove the transaction log files manually, there are certain prerequisites that
you need to accomplish before remove Exchange Server transaction log files-
a a) Database
states: Before the manual removal of any transaction log files, you should
determine the state of the particular database which you are using. There are
two states possible one is ‘attach’ which means that Exchange Server database
has not been shut down correctly, and another is ‘detach’ means the database is
shut down correctly. The state of the
database can be determined by using Eseutil
utility’s/ MH command switch.
b) Storage
groups: Before you begin the manual removal of Exchange transaction log file,
initially you should verify that each database is in a Clean Shutdown
(Consistent) state. In Storage groups, Exchange Server databases are organized
where these databases share a single transaction log file stream.
Below is a
complete set of steps to remove the excess transition log files manually:
1 1) Give a halt to the entire databases in the
storage group.
2 2) Now the verification of the state of each
database in the particular storage group is done.
3 3) Execute one of the following actions:
· If one or more of the databases are found in the Inconsistent (Dirty Shutdown) state, analyze which transaction log
files can be removed without affecting consistency
· If all the databases are found in the Consistent (Clean Shutdown)state then you can remove the entire
transaction log files except the current one.
4 4) Now at last, copy all the transaction which you
want to remove to a different location before removing them permanently from
the transaction log hard disk.
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