Introduction to Groups

A set of application processes can join a group. Each member of a group receives an ordinal, that is, a number representing its current position within the group. Application program logic uses the ordinal to select one of several possible operating roles.

A group server tracks the group members as processes join and leave the group, and as they disconnect from and reconnect to the server. At each of these events, the group facility revises ordinals to restore a one-to-one mapping between n members and the positive integers [1,n].

Developers are responsible for the names of groups, and for the API calls that join groups. Administrators are responsible for configuring group communication.

• Simple Fault Tolerance with Groups
  Application programs can use the group facility to coordinate fault-tolerant operation.
• Groups with More than Two Roles
  You can extrapolate fault-tolerant behavior to an application with several distinct operating roles.

Copyright © Cloud Software Group, Inc. All rights reserved.