25.1 Registry Hosts, Backup Registry Hosts, and Registry Regions

When you run the site preparation tool on a ClearCase networkwide release area, you designate one host in the local area network to be the ClearCase registry server host. The ClearCase albd_server program running on the registry server host acts as the registry server process: it responds to remote procedure call (RPC) requests from ClearCase hosts that need to read or modify registry data.

Access to the registry is critical for nearly all ClearCase operations. Because registry data is such an important resource, you can designate another ClearCase host as a backup registry server and periodically copy registry data to it using the rgy_backup command. If the primary registry server fails, you can run the rgy_switchover program to promote the backup registry server to be the primary registry server and reset all client hosts to use it.

Many registry entries include information that enables a ClearCase host to access a VOB or view over the network. Because the conventions for expressing network pathnames differ between UNIX and Windows, and because there may be other reasons why you need to register multiple network pathnames to a single VOB or view (perhaps the VOB or view is on a host that has multiple network interface cards and multiple host names), any ClearCase registry can support multiple registry regions. Each region is a consistent naming domain: all hosts in the same region must be able to access all VOB storage directories and view storage directories using the same network naming conventions. Registry regions are most often used when a mixed network of UNIX and Windows hosts need to access a common set of VOBs.

Every ClearCase host exists in exactly one network region. The cleartool hostinfo -long command displays a host's network region.

NOTE: Each VOB and view that resides on a host must have a tag in the host's registry region.