Overview

The application server infrastructure that is managed by a high availability manager includes cells and clusters. These components relate closely to core groups, high availability groups, and the policy that controls the high availability infrastructure.

Plan out how you need to set up your high availability environment to avoid the risk of a failure without failover coverage. As part of the planning process, understand how the high availability manager can assist you in controlling this type of an environment.

The high availability manager is designed to function in all of the supported WebSphere Application Server topologies. However, a high availability-managed environment must comply to the following rules:

• After you set up your WebSphere Application Server environment to comply with all of the high availability-managed environment rules, use the default core group to control this environment. DO NOT add additional core groups unless your environment absolutely requires them.

• Do not change the default configurations unless you are doing so to solve a specific problem or situation. When you do make configuration changes, such as changing the policy for a high availability group or moving core group members between core groups in a multi-core group environment, make sure you fully understand the effect such changes will have on your entire environment.

• A cell in a high availability infrastructure is partitioned into one or more core groups. WebSphere Application Server provides a default core group as part of the high availability manager function. Additional core groups can be created using the administrative console.

• A core group cannot extend beyond the boundaries of a cell, and it cannot overlap with any other core groups.

• A cluster must be a member of only one core group. All of the individual members of that cluster must be members of the same core group.

• Individual application servers are also members of a core group.

• All running members of a core group must be able to communicate with all of the other running members of that same core group.

While administering your core groups, you might need to perform one or more of the following tasks. These tasks can be performed in any order.

Procedure

1. Set up preferred coordinators
2. Change the number of core group coordinators.
3. Configure a core group transport.
4. Configure the discovery protocol for a core group.
5. Configure the failure detection protocol for a core group.
6. Configure a core group for replication
7. Configure core group IP caching.
8. Set up IP addresses for high availability manager communications for V6.0.2 and higher.
9. Configure core group socket buffers.
10. Specify a core group when adding a node.
11. Specify a core group when creating an application server.
12. View the core groups contained in a cell.
13. View the members of a core group.
14. Create a new core group.
15. Move core group members to a different core group.
16. View high availability group information
17. Create a new policy and associate it with a high availability group.
18. Change the policy associated with a high availability group.
19. Route high availability group work to a different server.
20. Create core group access points, if you have multiple core groups that need to communicate with each other.