You can move the Active Directory database and/or log files to a different partition, either for space or performance reasons, by using the Ntdsutil.exe tool:
1. Shutdown and restart your server in Directory Services Restore mode.
2. Log on as the Directory Services Restore mode administrator, using the password assigned during the Dcpromo process.
3. Open a CMD.EXE prompt and type ntdsutil.exe.
4. At the ntdsutil: prompt, type files.
5. At the file maintenance: prompt, type info and note the path of the database and log files.
6. To move the database, type:
move db to <target>
7. To move the log file, type:
move logs to <target>
8. Type quit 2 times, to return to the CMD prompt.
9. Shutdown and restart your server.