Network Deployment (Distributed operating systems), v8.0 > Establishing high availability > Configure core groups
Configure core group preferred coordinators
The high availability manager uses an ordered list of preferred core group servers when it selects servers to host the coordinators. If the default list is inappropriate, you can change the list such that other servers are selected as coordinators. Use the following guidelines to determine the appropriate ordered list of preferred coordinators:
- Make sure that you are familiar with the content of the Core group coordinator topic.
- Select a set of servers that infrequently start and stop, are stable, and that are located on capable systems with large amounts of system memory and a fast processor.
Even though it is possible to use a dmgr as a core group coordinator, IBM recommends that you use an application server that is not a dmgr. You might want to change the ordered list of preferred core group servers if:
- The system where the default coordinator is located has insufficient resources or capacity to serve as a coordinator.
- A server that normally gets selected as the coordinator starts and stops frequently.
To change the ordered list of preferred core group servers:
- In the admin console, click...
Servers > Core Groups > Core group settings and select an existing core group.
- Click Preferred coordinator servers and then add or delete the appropriate application servers from the list of preferred coordinator servers. Use Add and Remove to move servers into and out of the list of core group servers on which the coordinator service can run. Use Move up and Move down to adjust the order of the servers within this list. Make sure that the most preferred server is at the beginning of the list and the least preferred server is at the end.
- Click OK and then clickReview.
- Select Synchronize changes with nodes, and then click Save.
ResultsYour changes take effect immediately after synchronization completes. The members of the core group pick up these changes dynamically.
Preferred coordinator servers settings
Core groups (high availability domains)
Core group coordinator
Change the number of core group coordinators
Set up a high availability environment