Upgrading the DHCP Database to Windows NT Server 4.0

• Microsoft Windows NT Server versions 3.51 and 4.0

SUMMARY

When upgrading a Windows NT Server version 3.51 (or earlier) release to Windows NT 4.0, the DHCP database must be converted to the new database format. This conversion is required because the services now use 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.

MORE INFORMATION

When the DHCP service first starts after an upgrade to Windows NT 4.0, it detects that the database needs to be converted. It then starts a conversion process, Jetconv.exe. (If Jetconv.exe has already been started by another service, a second Jetconv.exe process is not started.) Prior to conversion, the user is notified that the conversion process is about to start and is asked for confirmation. If the user clicks OK, the DHCP service quits and the conversion begins. Jetconv.exe converts the databases of all the installed services (DHCP and, if installed, WINS and RPL) to the new Windows NT 4.0 database format.

After the DHCP database is converted successfully, the DHCP server service automatically restarts.

Before starting the conversion process, note the following guidelines:

• Prior to upgrading to Windows NT Server 4.0, bring the Windows NT 3.51 databases for the DHCP server to a consistent state. Do this by stopping the services from Control Panel\Services or by using the net stop service command.
• The conversion requires approximately the same amount of free diskspace 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 under the same directory where the original database and log files were located. On the DHCP server, this is the %SystemRoot%\System32\Dhcp\351db\ directory.

In cases where this automatic procedure of converting databases fails, the database can be converted manually using winntdir\system32\upg351db.exe. For instructions, type the following at the command prompt:

   upg351db -?

• You cannot convert the new database back to the previous database format.
• The converted database will not work with Windows NT 3.51 or earlier services.
• The new database engine uses log files named by using the prefix J50.