In a dual-partition upgrade, you divide the cluster into two groups of nodes. You bring down one group of nodes and upgrade those nodes. The other group of nodes continues to provide services. After you complete upgrade of the first group of nodes, you switch services to those upgraded nodes. You then upgrade the remaining nodes and boot them back into the rest of the cluster.
The cluster outage time is limited to the amount of time that is needed for the cluster to switch over services to the upgraded partition.
Observe the following additional restrictions and requirements for the dual-partition upgrade method:
Data format changes - Do not use the dual-partition upgrade method if you intend to upgrade an application that requires that you change its data format during the application upgrade. The dual-partition upgrade method is not compatible with the extended downtime that is needed to perform data transformation.
Location of application software - Applications must be installed on nonshared storage. Shared storage is not accessible to a partition that is in noncluster mode. Therefore, it is not possible to upgrade application software that is located on shared storage.
Division of storage - Each shared storage device must be connected to a node in each group.
Single-node clusters - Dual-partition upgrade is not available to upgrade a single-node cluster. Use the standard upgrade method instead.
Failover zone upgrade – You cannot upgrade failover zones if you are using the dual-partition upgrade method. You can only upgrade failover zones if you are using the standard upgrade or rolling upgrade method.
Configuration changes - Do not make cluster configuration changes that are not documented in the upgrade procedures. Such changes might not be propagated to the final cluster configuration. Also, validation attempts of such changes would fail because not all nodes are reachable during a dual-partition upgrade.