Applies to: Exchange Server 2007 SP3, Exchange Server
2007 SP2, Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2007-09-05
This section provides procedures related to recovering a failed database by performing a dial tone recovery on servers running Microsoft Exchange Server 2007. A dial tone recovery involves creating an empty database on a server to replace a failed database. This empty, or dial tone, database allows users to send and receive e-mail while the failed database is recovered. By using a dial tone recovery approach, you can restore basic e-mail service to users (providing them with a "dial tone") and then restore users' previous data as it becomes available.
This section provides information about several methods of performing a dial tone recovery:
- Dial tone recovery on the server with the failed database
- Dial tone recovery using an alternate server for the dial tone
- Dial tone recovery using and staying on an alternate server for
the dial tone database
All three methods use the following basic steps:
- Create a new empty dial tone database to replace the failed
database This new database will allow users
who had mailboxes on the failed database to send and receive new
messages. Exchange 2007 has a feature called dial tone
portability that allows you to point a user to a different
database without moving the mailbox. If you created the dial tone
database on a different server than the server that housed the
failed database, you will need to move the mailbox configuration to
that new server. For more information about the dial tone
portability feature, see Dial Tone
- Restore the old database Use whatever
backup and recovery software you typically use to restore the
failed database. If there is no backup of the failed database,
recover the failed database. If you are using the same server for
dial tone recovery, you need to restore the database to a recovery
storage group. For more information about recovery storage groups,
see Understanding Recovery
- Swap the dial tone with the restored
database After the failed database has been
restored, swap it with the dial tone database. This gives the users
the ability to send and receive e-mail and access all the data in
the restored database. If users were moved to a dial tone database
on another server, you then need to move the mailbox configuration
back to the original server.
- Merge the databases To get the data
from the dial tone database into the restored database, merge the
data. You can do this with the Database Recovery Management tool
included in the Exchange Management Console. For more information
about the Database Recovery Management tool, see Database Recovery
Management and Database Troubleshooter Tools.
The methods have different advantages and disadvantages as follows:
- Recovery on the server with the failed
database If a database fails on an
Exchange 2007 server and the server is still functional, it is
a best practice to perform a dial tone recovery on the server that
originally held the failed database. The reasons for this approach
are as follows:
- Your organization will have less downtime because you will not
need to move databases and configure mailboxes between servers. You
also do not need to reconfigure Outlook profiles.
- There are fewer steps to this procedure, which make it less
complex, with a smaller margin for error.
- Your organization will have less downtime because you will not need to move databases and configure mailboxes between servers. You also do not need to reconfigure Outlook profiles.
- Recovery using an alternate server for the dial tone
database If a server fails and needs to be
rebuilt, the most efficient way to give users basic mail
functionality is to quickly create a dial tone database on another
server, and move the mailbox configuration to that new server. Keep
in mind the following:
- This process will require that you move the dial tone database
back to the recovered server. This step adds more time to the
overall recovery process.
- This process is more complex than performing a dial tone
recovery on a single server.
- The server that you are temporally placing the dial tone
database on might not have sufficient resources to support the
added load of the additional users.
- Without Office Outlook 2007, you might have to
manually reconfigure users' Outlook profiles to point to the new
- This process will require that you move the dial tone database back to the recovered server. This step adds more time to the overall recovery process.
- Recovery using and staying on an alternate server for the
dial tone database Sometimes it isn't feasible
to recover the failed server. In this case, it might be necessary
to stay on an alternate server. If the server that you are using as
your alternate server has sufficient resources and can handle the
additional load, this might be a good opportunity to consolidate
For More Information
For more detailed procedures about performing a dial tone recovery, see the following topics: