Protecting host redundancy for significantly different hosts
Admission control helps to make sure there is spare capacity available in a cluster to keep the required level, redundancy, or reservations.
There are three types of policies available, which are as follows:
- Number of host failures a cluster tolerates
- Percentage of cluster resources reserved
- Specific failover hosts
When the requirement is to be able to lose one or more hosts and still be able to keep all the VMs needed running, the Host failures cluster tolerates option works quite well unless the hosts you are trying to protect have significantly different sizes—memory and CPU resources available.
This option for different hosts results in reserving an excessive capacity based on the size of the largest host. Reserving more capacity than required in its turn results in wasting resources.
For clusters with differently-sized hosts, VMware advice is to use the percentage of cluster resources reserved option. This option ensures...