If you use clustering on your systems, it is still important that you create a backup and recovery strategy to protect your data.
If you are planning on using clustering as your backup strategy so that you have one system up and running while the other system is down when its being backed up, it is recommended that you have a minimum of three systems in the cluster. By having three systems in the cluster, you will always have one system to switch over to should a failure occur.
Saving and restoring cluster resource groups
You can save a cluster resource group whether the cluster is active or inactive. The following restrictions apply for restoring a cluster resource group:
- If the cluster is up and the cluster resource group is known to that cluster, you cannot restore the cluster resource group.
- If the node is not configured for a cluster, you cannot restore a cluster resource group.
You can restore a cluster resource group if the cluster is active, the cluster resource group is not known to that cluster, the node is in the recovery domain of that cluster resource group, and the cluster name matches that in the cluster resource group. You can restore a cluster resource group if the cluster is configured but is not active on that node and if that node is in the recovery domain of that cluster resource group.
Preparing for a disaster
In the case of a disaster, you will need to reconfigure your cluster. In order to prepare for such a scenario, it is recommended that you save your cluster configuration information and keep a hardcopy printout of that information.
- Use the Save Configuration (SAVCFG) command or the Save System (SAVSYS) command after making cluster configuration changes so that the restored internal cluster information is current and consistent with other nodes in the cluster. See Saving configuration information for details on performing a SAVCFG or SAVSYS.
Print a copy of cluster configuration
information every time you change it. You can use the Display Cluster Information
(DSPCLUINF) command to print the cluster configuration. Keep
a copy with your backup tapes to use in case of a disaster where you want
to reconfigure your entire cluster.