Upgrading the DHCP Database for Windows 2000

When upgrading a Windows NT Server version 3.51 (or earlier) release for Windows 2000, the DHCP database must be converted to the new database format. The Windows 2000 database uses an improved database engine that is faster and compacts automatically to prevent fragmentation and consequent growth of the database. The database conversion procedure happens automatically as part of an upgrade installation.

When the DHCP service first starts after an upgrade to Windows 2000, it detects that the database needs to be converted. It then starts a conversion process by running a program called Jetconv.exe. The DHCP service stops and the conversion begins. Jetconv.exe finds and converts the databases for all of the installed services (DHCP and, if installed, WINS) to the new Windows 2000 database format.

After the DHCP database is converted successfully, the DHCP service is automatically restarted.

Note

Prior to upgrading to Windows 2000, bring any Windows NT 3.51 or 4.0 databases for the DHCP server up to a consistent state. Do this by terminating the services, either by using the Service utility in Control Panel or by using the net stopservice command. This is recommended because it prevents the Jetconv.exe conversion from failing due to an inconsistent Windows NT 3.51 or 4.0 database.

The conversion requires approximately the same amount of free disk space as the size of the original database and log files. You should have at least 5 MB free for the log files for each database.

The conversion process preserves the original database and log files in a subdirectory named 351db (if from Windows NT 3.51) or 40db (if from Windows NT 4.0) under the same directory where the original database and log files were located. On a DHCP server, this is the % SystemRoot %\System32\Dhcp\ version db directory. The administrator can later remove these files to reclaim the disk space.

The database conversion can take anywhere from a minute to an hour depending on the size of the database. The user must not restart the services while the databases are being converted. To check the status of the conversion, use Event Viewer to watch the application event log of the Jetconv.exe process.

In case this automatic procedure of converting databases fails for some reason (as can be determined from the event logs), the database that could not be converted can be converted manually using % SystemRoot %\System32\ upgversiondb .exe.

The new database engine uses log files named by using the prefix J50 .

Warning

You cannot convert the new database back to the previous database format. The converted database does not work with Windows NT 3.51 or earlier versions of DHCP services.