vcix-dcv-design math – Get remaining host cpu capacity

Although these are typical question for vmware design exams, (vcap-dcd, vcix-dcv-design) they are fundamental in calculating available capacity given a specific number of tolerable host failures
What percentage of cluster resources does your cluster still have to start VM’s in the event of a failure with x admission control reservation.
In other words, after setting admission control (see here) you want to calculate the percentage of actual available resources (GHz and GB) left on your cluster
total host resource

12 hosts
2x8core 2.2GHz  – 12 x 2 x 8 x 2.2 = 422 GHz
128GB of Memory – 12 x 128 = 1536 GB

total VM requirements 
200Ghz CPU,
624GB Memory.

Current admission control reservation
33%

To work out what percentage of cluster resources your cluster has available to start VM’s in the event of  host failures with x admission control reservation.

((total host resources – total vm requirements) / total host resources) = total failover capacity – current failover reservation = available additional failover capacity

CPU calculation ((422.4GHz – 200GHz)/422.4GHz) = 53% – 33% Reservation = 20%
Memory calculation ((1536GB – 624G)/1536GB) = 59% – 33% Reservation = 26%

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