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Q247109: XADM: Steps to Restore an Online Backup Using Current Log Files |
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Article: Q247109
Product(s): Microsoft Exchange
Version(s): 4.0,5.0,5.5
Operating System(s):
Keyword(s): exc4 exc5 exc55
Last Modified: 06-AUG-2002
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The information in this article applies to:
- Microsoft Exchange Server, versions 4.0, 5.0, 5.5
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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:
1. 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.
2. 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:
a. 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.
b. 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
c. 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.
3. If there is only a single server in the site, to restore the Exchange Server
directory:
a. 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.
b. 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.
c. 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.
d. 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.
e. 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."
f. 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.
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.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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."
8. 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.
9. 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.
Additional query words:
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Keywords : exc4 exc5 exc55
Technology : kbExchangeSearch kbExchange500 kbExchange550 kbExchange400 kbZNotKeyword2
Version : :4.0,5.0,5.5
Issue type : kbhowto
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