Moira is a database and primary information repository for:
- Workstation cluster information
- Locker filsys entries, quotas, and server locations
- Lists, which compasses mailing lists and filesystem access groups
- Host and network configuration
- Kerberized NFS server configuration
- Printer configurations
- User information
- Zephyr ACLs
- "Generic ACLs" which can be used by any service which can be made to understand the ACL file format
and probably a few other things.
Production systems never (at least, ideally) retrieve information from moira as part of regular operation; instead, a periodic process called a DCM (Data Control Manager) pushes out new versions of information from the Moira database to the affected servers. For instance, the Hesiod DNS servers are periodically updated with a new zone file containing new cluster, filsys, printer, and user information. Currently, the DCM runs several times a day. A few kinds of changes to the Moira database are propagated immediately to the affected servers via incremental update; an example is changes to AFS groups resulting from changes to Moira list membership.
The Moira server is implemented as an Oracle database with a surrounding layer of C code. The Moira clients for Unix live in the moira locker (the Athena release contains scripts which attach the moira locker and run the actual programs), and use Kerberos 4 to authenticate to the Moira server.