12.12 Certain Branches Are Shared Among MultiSite Sites

PRODUCT NOTE: Rational ClearCase LT does not support ClearCase MultiSite.

If your company uses ClearCase MultiSite to support development at different sites, you must tailor your branching strategy to the needs of these sites. The standard MultiSite development model is to have a replica of the VOB at each site. Each replica controls (masters) a site-specific branch type, and developers at one site cannot work on branches mastered at another site. (For more information on MultiSite mastership, see the Administrator's Guide for Rational ClearCase MultiSite.)

However, sometimes you cannot, or may not want to, branch and merge an element. For example, some file types cannot be merged, so development must occur on a single branch. In this scenario, all developers must work on a single branch (usually, the main branch). MultiSite allows only one replica to master a branch at any given time. Therefore, if a developer at another site needs to work on the element, mastership of the branch must be transferred to that site.

MultiSite provides two models for transferring mastership of a branch:

• The push model, in which the administrator at the replica that masters the branch uses the chmaster command to give mastership to another replica.

This model is not efficient in a branch-sharing situation, because it requires communication with an administrator at a remote site. For more information about this model, see the Administrator's Guide for Rational ClearCase MultiSite.

• The pull model, in which the developer who needs to work on the branch uses the reqmaster command to request mastership of it.

NOTE: The developer can also request mastership of branch types. For more information, see the Administrator's Guide for Rational ClearCase MultiSite.

This model requires the MultiSite administrators to enable requests for mastership in each replica and to authorize individual developers to request mastership. If you decide to implement this model, you must provide the following information to your MultiSite administrator:

• Replicated VOBs that should be enabled to handle mastership requests

• Identities (domain names and user names) of developers who should be authorized to request mastership

• Branch types and branches for which mastership requests should be denied (for example, branch types that are site specific, or branches that must remain under the control of a single site)

The Administrator's Guide for Rational ClearCase MultiSite describes the process of enabling the pull model and a scenario in which developers use the pull model. The Developing Software manual describes the procedure developers use to request mastership.