Hosts
A host is a managed system in HMC that is primarily used to run the virtual machines that runs the workload. A host can also be called as a server or a Central Electronics Complex (CEC). Hosts are identified by its universal unique identifier (UUID) as tracked in the HMC.
- Host pair
- Indicates the set of hosts that are paired across the sites for high-availability and disaster
recovery.
Each host in the host pair must meet all the resource requirements (for example, CPU, memory, VIOS-based virtual I/O aspects) to run the same workload in a disaster or a potential disaster.
- Host group
- Indicates a group of hosts that are logically chosen and named by the administrator.
You can group a set of hosts based on your business requirements. Each host must belong to a host group. For example, you can group the hosts that run similar type of workloads. Or, you can group the most important hosts together so that the monitoring and recovery operations can be performed for the set of hosts together and quickly. By grouping the most important hosts in their own group, in the event of a disaster, you can move the host group to the backup site.
You can perform discovery, verification, move, and recovery operations at host group level. If you run these operations at site level, all the host groups are included in the operation. If a host group is already moved to the backup site, and then a site-level move operation is started from the home site, that host group is skipped for the operation.
The following figure shows the host-related configuration across sites:
Host pairing is not required in an asymmetric host group configuration.