How the Registry Database is Stored
Each security server maintains a working copy of the registry database in virtual memory and a permanent copy on disk. All reads and updates operate on the copy that is in virtual memory. The servers use the copy that is on disk to initialize the copy in virtual memory when they start up. An atomic update log is used to guarantee the database state in the event of server failure.
The following figure shows the server and the disk and virtual memory copies of the registry database.
Disk Memory and Virtual Memory Copies of the Registry Database
Each security server periodically saves its entire database from virtual memory to disk. The database is stored in dcelocal/var/security/rgy_data.