Novell GROUPWISE 7 - INTEROPERABILITY GUIDE, Manual

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Planning GroupWise in a Heartbeat Cluster 291
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the physical IP address of the node. Secondary IP addresses are created by setting up IP address
resources, as described in
Section 30.1.4, “Planning Secondary IP Addresses,” on page 287 . The IP
address resource moves with each agent when it fails over, so that, in the case of the POA,
GroupWise clients do not lose their connections to the POA. When you use the
Configure
GroupWise for Clustering option, the GroupWise Installation program sets the --ip switch in each
agent startup file to its unique secondary IP address.
If you are going to set up a GroupWise name server to help GroupWise clients locate their post
offices, make sure that the default POA port number of 1677 is used somewhere in the cluster. For
more information, see “
Simplifying Client/Server Access with a GroupWise Name Server ” in “ Post
Office Agent ” in the GroupWise 7 Administration Guide .
30.6.2 Determining Appropriate Heartbeat Constraints for
GroupWise Cluster Resource Groups
By default, a cluster resource group has all nodes in the cluster available for failover. Only one node
at a time can have a particular cluster resource group mounted and active. If a cluster resource
group’s initial node fails, the resource group fails over to another node in the cluster.
You should customize the Heartbeat constraints for each GroupWise cluster resource group based on
the fan-out-failover principle. When a node fails, its cluster resource groups should not all fail over
together to the same node. Instead, the resource groups should be distributed across multiple nodes
in the cluster. This prevents any one node from shouldering the entire processing load typically
carried by another node. In addition, some cluster resource groups should never have the potential of
being mounted on the same node during a failover situation. For example, a post office and POA
that service a large number of very active GroupWise client users should never fail over to a node
where another very large post office and heavily loaded POA reside. If they did, users on both post
offices would notice a decrease in responsiveness of the GroupWise client.
When you create a Heartbeat constraint, you give it a unique ID, associate it with one or more
cluster resource groups, and provide information specific to the constraint type. Heartbeat offers
three types of constraints that control the failover behavior of cluster resource groups in the cluster.
A cluster resource group can use multiple types of constraints to assure the desired failover behavior.
Š
“Place Constraint” on page 292
Š
“Order Constraint” on page 292
Š “Colocation Constraint” on page 292
GROUPWISE CLUSTERING WORKSHEET
Under Item 3: MTA Network Information , select an IP address resource from the Heartbeat Clustering
Worksheet ( item 5 ) and record the secondary IP address associated with the IP address resource on the
GroupWise Clustering Worksheet.
Under Item 5: POA Network Information , select an IP address resource from the Heartbeat Clustering
Worksheet ( item 5 ) and record the secondary IP address associated with the IP address resource on the
GroupWise Clustering Worksheet.