Set up your system to be highly available, which includes
configuring the high availability infrastructure this product supports,
and having your applications take advantage of it.
Setting up a high availability environment
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.
High availability manager
The product includes a high availability manager component.
The services that the high availability manager provides are only
available to product components.
Disabling or enabling a high availability manager
A unique HAManagerService configuration object exists for
every core group member. The enable attribute in this configuration
object determines if the high availability manager is enabled or disabled
for the corresponding process. When the enable attribute is set to true,
the high availability manager is enabled. When the enable attribute
is set to false, the high availability manager is disabled.
By default, the high availability manager is enabled. If the setting
for the enable attribute is changed, the corresponding process must
be restarted before the change goes into effect. You must use the
wsadmin tool to disable or enable a high availability manager.
Viewing high availability group information
High availability
groups are dynamically created components of
a core group. They cannot be configured directly, but they are directly
affected
by static data, such as policy configurations, which is specified
at the core
group level. You can use the administrative console to view information
about
the high availability groups that are part of a core group.
Creating a policy for a high availability group
Every high availability group has to have an associated
policy. This policy determines which members of a high availability
group to put in the active state.
Selecting the policy for a high availability group
Every high availability group has an associated policy.
The high availability manager uses this policy to determine which
members of a high availability group to put in the active state.
Creating a new core group (high availability domain)
A default core group, called DefaultCoreGroup, is created for each
cell. This default core group or high availability domain as it is sometimes
referred to, is sufficient in most configurations. However there are some
circumstances under which you need to create additional core groups for a
cell.
Viewing the core groups in a cell
A core group is a component of the high availability manager. A
default core group, called DefaultCoreGroup, is created for each cell. A core
group can contain application servers, proxy servers, node agents, and the
deployment manager. A core group must contain at least one node agent or the
deployment manager.
Viewing core group members
A core group member is an application server, proxy server, the
deployment manager, or a node agent that is a member of a high availability
core group.
Moving core group members
When moving members to a different core group, remember
that: each process can only be a member of one core group, and that
all members of a given cluster must belong to the same core group.
Configuring the core group bridge service
The core group bridge service can be configured to establish
communication between core groups. A core group is a statically defined
component of the high availability manager. To configure communication
between core groups, use an access point group. An access point group
is a collection of core groups that communicate with each other.
Establishing high availability for Data access resources
This page provides a starting point for finding information
about data access. Various enterprise information systems (EIS) use
different methods for storing data. These backend data stores might
be relational databases, procedural transaction programs, or object-oriented
databases.
Establishing high availability for Transactions This page provides a starting point for
finding information about Java Transaction
API (JTA) support. Applications running on the server can use transactions
to coordinate multiple updates to resources as one unit of work, such
that all or none of the updates are made permanent.
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