wiki:Moira

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.