Microsoft KB Archive/247109

= XADM: Steps to Restore an Online Backup Using Current Log Files =

Article ID: 247109

Article Last Modified on 10/27/2006

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APPLIES TO


 * Microsoft Exchange Server 4.0 Standard Edition
 * Microsoft Exchange Server 5.0 Standard Edition
 * Microsoft Exchange Server 5.5 Standard Edition

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This article was previously published under Q247109



SUMMARY
This article describes how to restore an Exchange Server-aware online backup, explains the most common reason that an online restoration may not work, and provides steps to include current log files (any files that were created after the last online backup) with files from the online restoration process to recover the most current data possible.



MORE INFORMATION
For example, if a full online backup is taken on Wednesday night, an incremental backup is taken Thursday night, and the Exchange Server computer disk that contains the information store and directory databases fails (or "crashes") on Friday afternoon, the transaction log folders are intact and include all of the transaction log files for Friday after the online incremental backup that was taken on Thursday night. Before the full online backup was taken on Wednesday night, circular logging must have been turned off.

In Exchange Server-aware backup software, you can usually either select an option to "erase existing data" or clear a "no-loss restoration" option. However, even when you use these settings, version or signature conflicts may arise between log files and databases when you restore an online backup that can prevent the restoration from working. This is the single most common reason that the restoration of an online backup of Exchange Server may not work. This article provides detailed steps that you can take to avoid this problem and other common problems, and to successfully restore an online backup of Exchange Server.

Restoring the Online Backup
Make sure that you back up all of the files in all of the Dsadata and Mdbdata folders to flat file copies on a disk and that you include all of the .edb, .log, and .chk files. If you do this and there are problems with the tape backups, you still have a database on a disk that you can gain access to and repair if necessary. Do not delete these flat file copies until after you restore the online backup of Exchange Server and Exchange Server runs successfully for a few days.

Because the information store service depends on the Exchange Server directory service, and the information store is usually larger and takes longer to restore, Microsoft recommends that when you restore an online backup of Exchange Server, you restore the online backup in two steps:
 * Restore only the Exchange Server directory, and then make sure that the directory service runs properly.
 * Restore the Exchange Server information store as a separate step.

Restoring the Exchange Server Directory
 Make sure that you have backed up all of the files in the Dsadata subfolders on all of the logical drives. There can be up to three Dsadata folders on different drives: one for the Dir.edb database, one for the Edb.log files, and one for the Edb.chk file. Check all of the logical drives on the computer for an Exchsrvr subfolder and then check those folders for the presence of a Dsadata folder. After you back up all of the Dsadata folders to flat file copies, delete everything in the Dsadata folders on all of the logical drives. If the Exchange Server computer is in a site that contains multiple servers and can connect to other servers in the site, to restore the Exchange Server directory:  Simply restore the directory from the most recent full online backup (in the example above, the Wednesday night backup). You do not need to restore all of the incremental log files and current log files that were generated after the most recent online backup (in the example, the incremental log files from Thursday and the current log files from Friday) because when the directory service starts after an online backup is successfully restored, the Exchange Server computer contacts the other servers in the site and obtains any data that was generated after the most recent online backup. In your online backup program, make sure that you do not select the option to automatically start the Exchange Server directory service after the backup is restored. Do not start the Exchange Server directory manually after you restore the online backup. Record the names of all of the files in all of the Dsadata folders after you restore the online backup. Check the application event log to determine which event is the most current. Close the application event log. Manually start the Exchange Server directory service by performing one of the following steps:  In Control Panel, double-click Services, and then start the directory service. -or-

 At a command prompt, type the following command:

Net Start MSExchangeDS

</ul> </li> Open the application event log, check for new events, and make sure that there are no errors starting the directory service. If there are no errors, go directly to the "Restoring the Exchange Server Information Store" section of this article. If the directory does not start, clear out all of the Dsadata folders again, and try to restore the directory from an earlier backup. Because the directory obtains any data that was generated after the backup in a multiserver environment, if you use an older backup, you do not lose data.</li></ol> </li> If there is only a single server in the site, to restore the Exchange Server directory: <ol style="list-style-type: lower-alpha;"> Restore the directory from the most recent full online backup. In your online backup program, make sure that you do not select the option to automatically start the Exchange Server directory service after the backup is restored. Do not start the Exchange Server directory manually after you restore the online backup. After you restore the online backup, record the names of all of the files in all of the Dsadata folders.</li> Restore the incremental backups that were taken for the directory in the order they were created, beginning with the oldest one first and finishing with the most recent one. In your backup program, make sure that you do not select the option to automatically start the Exchange Server directory service after the incremental backups are restored. Do not start the Exchange Server directory manually after you restore the incremental backups. After you restore the incremental backups, add the names of all the new files in all of the Dsadata folders to the list of file names that you started in step 3a.</li> Manually copy the Edbxxxxx.log files only (where xxxxx is a series of hexadecimal digits, for example, Edb00001.log) from the backup of the Dsadata log folder for the time after the last incremental backup was taken (in the example above, the Edbxxxxx.log files for Friday). Make sure that these Edbxxxxx.log files are in sequence with the other Edbxxxxx.log files, including the Edb.log file itself. The current log file is always the Edb.log file. The log files are generated in sequential order by using hexadecimal numbers for the names. To make sure that the Edbxxxxx.log files are sequence and that there are no missing log files, read the names of the files in hexadecimal or convert the hexadecimal values to decimal by using Scientific view of the Calculator utility (click Start, point to Programs, point to Accessories, and then click Calculator).

Do not copy any other files (such as .chk files, Res.log files, and Hierarch.dat files) from the temporary Dsadata backup folders.</li> If the server was shut down because of a disk failure or a power failure and the server was not shut down "gracefully" (for example, if a hardware failure did not allow the current data from memory to be transferred to disk), do not copy the Edb.log file itself, because the Edb.log file may cause problems during the restoration. If the server was shut down "gracefully," include the actual Edb.log file when you copy the Edbxxxxx.log log files from the Dsadata temporary backup folder.</li> IMPORTANT: Do not check the Dir.edb database from the online restoration for consistency by using the eseutil /mh or edbutil /mh commands, now or at any point during the online restoration process. This database from the online restoration is automatically inconsistent because this is an online restoration, and Exchange Server only produces offline databases that are consistent if a server is shut down "gracefully."</li> Open the application event log and determine which event is the most current. Close the application event log. Manually start the Exchange Server directory service in Control Panel, Services. Open the application event log, check for new events, and make sure that there are no errors starting the Exchange Server directory service. If there are no errors, you have successfully restored the Exchange Server directory service, and you are now ready to restore the information store.</li></ol> </li></ol>

Restoring the Exchange Server Information Store

 * 1) Make sure that you have a complete backup of all of the files in all of the Mdbdata folders on all of the drives on the computer. Then delete all of the files in the Mdbdata folders on all of the logical drives.
 * 2) IMPORTANT: Select the option to restore both the private information store and the public information store. This is a required step.

If you select either the private information store only or the public information store only, the restoration may not work and you may have to perform the steps to restore the directory again starting from the beginning, which can be a lengthy process, depending on the size of the information store databases.
 * 1) Restore the information store from the most recent online backup (in the example above, the Wednesday night backup). Do not start the Exchange Server information store manually after you restore the most recent online backup. After the restoration has finished, record the names of all of the files in all of the Mdbdata folders.
 * 2) Restore the incremental backups that were taken for both the private information store and the public information store in the order that they were created, beginning with the oldest one first and finishing with the most recent one. Do not start the Exchange Server information store manually after you restore the incremental backups. After you restore the incremental backups, add the names of all of the new files in all of the Mdbdata folders to the list of file names that you started in step 3.
 * 3) Manually copy the Edbxxxxx.log files only (where xxxxx is a series of hexadecimal digits, for example, Edb00001.log) from the backup of the Mdbdata log folder for the time after the last incremental backup was taken (in the example above, the Edbxxxxx.log files for Friday). Make sure that the Edbxxxxx.log files are in sequence with the other Edbxxxxx.log files, including the Edb.log file itself. The current log file is always the Edb.log file. The log files are generated in sequential order by using hexadecimal numbers for the names. To make sure that the Edbxxxxx.log files are sequence and that there are no missing log files, read the names of the files in hexadecimal or convert the hexadecimal values to decimal by using Scientific view of the Calculator utility (click Start, point to Programs, point to Accessories, and then click Calculator).

Do not copy any other files (such as .chk files, Res.log files, and Tmp.edb files) from the temporary Mdbdata backup folders.
 * 1) If the server was shut down because of a disk failure or a power failure and the server was not shut down "gracefully" (for example, if a hardware failure did not allow the current data from memory to be transferred to disk), do not copy the Edb.log file itself, because the Edb.log file may cause problems during the restoration. If the server was shut down "gracefully," include the actual Edb.log file when you copy the Edbxxxxx.log log files from the Mdbdata temporary backup folder.
 * 2) IMPORTANT: Do not check the Priv.edb and Pub.edb from the online restoration for consistency by using the eseutil /mh or edbutil /mh commands, now or at any point during the online restoration process. These databases from the online restoration are automatically inconsistent because this is an online restoration, and Exchange Server only produces offline databases that are consistent if a server is shut down "gracefully."
 * 3) IMPORTANT: Do not run the isinteg -patch command. This is an online restoration and the isinteg -patch command is run internally by the Exchange Server-aware backup program behind the scenes.
 * 4) Check the application event log to determine which event is the most current. Close the application event log. Manually start the Exchange Server information store service in Control Panel, Services. Open the application event log, check for new events, and make sure that there are no errors starting the Exchange Server information store service. If there are no errors, you have successfully restored the Exchange Server information store service.

Check the contents of a few mailboxes to make sure that the mailboxes are populated with messages and mailbox folders. Check mail flow by sending messages to other Exchange Server users with delivery receipt requested (in Microsoft Outlook, in the test message, click Properties on the File menu, and then click to select the Delivery receipt requested check box before you send the test message).

If the messages are delivered, immediately perform a full Exchange Server-aware online backup (use full backup software logging and check the log for errors after the backup is finished) to ensure a current valid online backup of Exchange Server.

Keywords: kbhowto KB247109

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