The high availability framework that is provided with the
product eliminates single points of failure and provides peer to peer
failover for applications and processes running within the product
environment. This infrastructure is managed by a high availability
manager and includes cells, clusters, core groups, and high availability
groups. Every high availability group has a policy associated with
it that the high availability manager uses to determine which members
of a high availability group are active at a given time.
Before you begin
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 environment.
About this task
The high availability manager is designed to function
in all of the supported product topologies. However, a high availability-managed
environment must comply with the following rules:
- A cell in a high availability infrastructure is partitioned into
one or more core groups. The product provides a default core group
as part of the high availability manager function. You can use the
administrative console to create additional core groups.
- 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
- Enable the high availability
manager if it is not already enabled.
- View information about the high availability groups, core groups, and core group members.
- Create a new policy
and associate it with a high availability group.
- Change the policy that
is associated with a high availability group.
- Create a new core group.
- Change the configuration settings for a core group.
While running your applications in a highly available environment,
you might want to
move core group
members to a different core group. You also might want to change
one or more of the following:
- Configure a transport
for a core group.
If you are using an IIOP transport,
you might also need to complete one or more of the following actions:
- Specify a core group
when you add a node.
- Specify a core group
when you create an application server.
- Set up a core
group bridge.
If you are using multiple core
groups and members of different groups need to communicate with each
other, you must set up a core group bridge to enable this communication.
- Set
up a sysplex that is highly available.
- Control
application rollout and workload routing in a high availability
configuration.
- Manually
update a high availability application.
What to do next
After you set up your product environment to comply with
all of the high availability-managed environment rules, use the default
core group to control this environment.
Avoid trouble: Do not add core groups unless you cannot properly perform
without them. Also, do not change the default configurations unless
doing so provides the solution to a specific problem. When you do
make configuration changes, such as changing the policy for a high
availability group or moving core group members between core groups,
make sure you fully understand the effect such changes have on your
entire environment. Such changes might affect application processing.
gotcha
Read the topic High availability environment troubleshooting tips if you encounter
problems while running applications in your high availability environment.