The guardian database (ngwguard.db) serves as a reference for the following subordinate databases in the post office:
The guardian database stores information that is common among all databases, thus eliminating duplication of information. The subordinate databases reference information stored in the guardian database. The benefits of the guardian database include the following:
Single Reference Point: The guardian database stores information for each post office. Instead of storing the dictionary information in multiple dictionary databases, it is stored once in the guardian database.
Increased Performance: When the information in the guardian database is accessed, it is written to cache memory. Each subsequent request can be handled with information already available in cache memory, which is faster than disk access.
Tracking Attachments and Documents: When an attachment or document becomes orphaned (loses pointers to the message or profile), the guardian database is used to re-locate the origination of the attachment or document.
GroupWise Remote Management: When a user starts GroupWise Remote, a local guardian database is created on the remote workstation to store information similar to the guardian database in the remote user's post office in the master system.
The guardian database is vital to GroupWise functioning. Therefore, the POA has an automated back-up and roll-forward process to protect it. The POA keeps a known good copy of the guardian database called ngwguard.fbk. Whenever it modifies the ngwguard.db file, the POA also records the transaction in the roll-forward transaction log called ngwguard.rfl. If the POA detects damage to the ngwguard.db file on startup or during a write transaction, it goes back to the ngwguard.fbk file (the "fall back" copy) and applies the transactions recorded in the ngwguard.rfl file to create a new, valid and up-to-date ngwguard.db.
In addition to the POA back-up and roll-forward process, you should still back up the ngwguard.db, ngwguard.fbk, and ngwguard.rfl files regularly to protect against media failure. Without a valid ngwguard.db file, you cannot access your e-mail. With current ngwguard.fbk and ngwguard.rfl files, you can rebuild a valid ngwguard.db file should the need arise.
The ngwguard.dc file is the structural template for building the guardian database and its subordinate databases. Also called a dictionary file, the ngwguard.dc file contains schema extension information, such as administrator-defined fields, data types, and record indexes. If this dictionary file is missing, no additional databases can be created in the post office.