Performing key maintenance on a VMware Infrastructure 3 (VI3) host OS or can be an involved process, as can the process of simply adding a host. Because of the length of time that a system may be offline or because of what exactly is being performed, having the hosts in an isolated cluster can allow a safe environment for virtually any task. An isolated cluster will not apply to the same DRS and high availability rules that may apply to the live cluster. Further, you can reboot the host as needed without needing to wonder if there will be any effect to the live workload.
With the isolated cluster, the following tasks can be safely performed:
-Version upgrades (ESX 3.0x to 3.5 Update 1)
-Adding a new host to an existing cluster
-Testing network connectivity to various port groups
-Confirming VMware HA and DRS performance with in an isolated set of rules
-Importing or configuring new storage types
A good practice for the isolated cluster would be to keep it less visible to the live workload and named accordingly within the VMware Infrastructure Client, so a name like “TestingCluster” or “ZZUpgradeCluster” can distinguish the collection to be different from that of the live workload.
The figure below shows a cluster with a name and position that contains one host in maintenance mode for any task better suited in an isolated environment:
It is important to note that this cluster would still require licensing as it would be in live workload cluster. More information on creating a VI3 cluster can be found in the VI3 online library.