Technical Considerations for a Serviceguard Cluster that Spans Multiple IP Subnets, July 2009

 Same domain name for all nodes in the cluster

 Maximum 200 millisecond latency in the heartbeat network

 Nodes fully connected at the IP level

 Minimum of two separate, statically routed heartbeat subnets

 Standby interfaces on each node for each package subnet or IP Monitor configured for each

package subnet

 Packages configured to fail over across subnets should be modular rather than legacy

Cross-subnet configurations provide considerable benefits in the area of network architecture and

administration, but can also pose challenges for application deployments. These challenges stem from

the fact that a package’s relocatable IP address will change when the package fails over to a node

on a different subnet. This means that you need to take into account not only the cluster and package

configuration requirements and recommendations described here, but also the technical

considerations for application deployment. It is particularly important to analyze all client applications

that connect to the clustered applications if and how they can cope with the change of the IP address

after a cross-subnet failover. For some applications it might be necessary to restart all clients after a

cross-subnet failover.

For more information

To learn more about HP Serviceguard Solutions for high availability and disaster recovery,

please visit:

www.hp.com/go/serviceguardsolutions

For technical documentation:

www.docs.hp.com/hpux/ha

Packard Development Company, L.P. The information

contained herein is subject to change without notice. The only warranties for HP

products and services are set forth in the express warranty statements

accompanying such products and services. Nothing herein should be construed as

constituting an additional warranty. HP shall not be liable for technical or editorial

errors or omissions contained herein.

July

2009