Synchronizing The Cluster Definition Across Nodes - IBM AIX HACMP SG24-5131-00 Hardware User Manual

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It is highly unlikely that you will add or remove a network module. For
information about changing a characteristic of a Network Module, such as the
failure detection rate, see the chapter on changing the cluster topology in the
HACMP for AIX, Version 4.3: Administration Guide , SC23-4279. Changing
the network module allows the user to influence the rate of heartbeats being
sent and received by a Network Module, thereby changing the sensitivity of
the detection of a network failure.
In HACMP/ES, topology services and group services are used instead of
Network Interface Modules (NIMs) in order to keep track of the status of
nodes, adapters or resources.
In HACMP/ES, the tuning of network sensitivity is a little different.
Customizable attributes are the interval between heartbeats in seconds and
the Fibrillate Count, which is the acceptable number of missed heartbeats
before some event is triggered. You will find the Change / Show Topology
and Group Services Configuration in the Cluster Topology screen, just
like the NIM tuning options.

4.2.5 Synchronizing the Cluster Definition Across Nodes

Synchronization of the cluster topology ensures that the ODM data on all
cluster nodes is in sync. The HACMP ODM entries must be the same on each
node in the cluster. If the definitions are not synchronized across nodes, the
HACMP for AIX software generates a run-time error at cluster startup.
Even if you have a cluster defined with only one node, you must still
synchronize the cluster.
The processing performed in synchronization varies depending on whether
the cluster manager is active on the local node. If the cluster manager is not
active on the local node when you select this option, the ODM data in the
system default configuration directory (DCD) on the local node is copied to
the ODMs stored in the DCDs on all cluster nodes. The cluster manager is
typically not running when you synchronize the initial cluster configuration.
If the cluster manager is active on the local node, the ODM data stored in the
DCDs on all cluster nodes are synchronized. In addition, the configuration
data stored in the active configuration directory (ACD) on each cluster node is
overwritten with the new configuration data, which becomes the new active
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