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This article describes how to free hard disk space from Exchange Server databases if there is insufficient free disk space to carry out an offline defragmentation.
The Eseutil utility can perform an offline defragmentation, which releases unused hard drive space from Exchange Server databases to the file system. Eseutil requires free hard disk space equal to at least 110 percent of the database size (to create a temporary database that is used in the defragmentation).
If no local drive has sufficient space for an offline defragmentation, you can use one of the three following options, which are expanded on in the "More Information" section of this article:
Eseutil is a part of the Exchange Server 5.5 installation and is located in the Winnt\System32 folder. Eseutil can perform an offline defragmentation, which releases unused hard disk space from Exchange Server databases to the file system. Online defragmentation, which the information store runs during the scheduled online information store maintenance period, does not release disk space to the file system. The amount of space that Eseutil releases is approximately equal to the amount of unused space in the databases. For additional information about how to determine free space in the Exchange Server databases, click the following article number to view the article in the Microsoft Knowledge Base:
195914Offline defragmentation requires free hard disk space of at least 110 percent of the database size. For example, Eseutil requires up to 1.10 gigabytes (GB) of free space to defragment a 1-GB Priv.edb database. Eseutil uses this hard disk space to create a temporary database that the defragmentation process uses. By default, Eseutil creates this database in the current working folder of the command prompt session from which Eseutil runs. For additional information about Eseutil free disk space requirements, click the article number below to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/195914/ )Determining database free space with Exchange 5.5 Service Pack 1 and later versions of Exchange
(http://support.microsoft.com/kb/183888/EN-US/ )XADM: Free Disk Space Requirements for Eseutil.exe
Offline Defragmentation with Redirected Temporary DatabaseYou can use free space on another local or network drive by specifying the path and file name for the temporary database. The specified path must be on a lettered drive, not in a Universal Naming Convention (UNC) path. For example, C:\path_name_1\path_name_2\Tmpdfrg.edb is acceptable, but \\file_server\sharepoint\tmpdfrg.edb is not allowed.
You can add a temporary physical drive to the server specifically for defragmentation. You can also map a network drive by using the net use command.
The following sample command specifies the temporary database path and file name G:\Folder1\TempDfrg.edb:
eseutil /d /ispriv /tG:\Folder1\TempDfrg.edbNotice that there is no space between the /t and the drive letter.
Note After you defragment your database offline, it has a new signature that does not match the signature in the old log files. Retention of the old log files causes the database to fail to start and the following event ID 143 error message is logged:
"The database signature does not match the log signature for database."Because the database was shut down correctly before you defragmented it, all the data was written to the database. You can safely move the log files from the production location to a temporary location. Then you can start the database.
Moving Information to Another Server and Recreating Empty DatabasesWarning Before you perform the following procedure, back up all Exchange Server databases and verify the databases' integrity. If you do not back up your databases, you may permanently damage or lose your databases.
You can move all of the information from an information store database to another server and then recreate an empty database in the information store database's place to effectively free disk space. If the information store does not find a database where a database should exist, the information store service recreates an empty database.
To move information to another server and recreate empty databases:
Offline Defragmentation on Another ComputerYou can also move the databases to another computer that Microsoft Exchange Server is not installed on and run Eseutil on that computer. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/244525/EN-US/ )XADM: How to Run Eseutil on a Computer Without Exchange Server
Quick ReferenceThe following outline provides a quick reference of the options that are available to free hard disk space from Exchange Server databases.
Article ID: 255035 - Last Review: October 27, 2006 - Revision: 5.2