This doesn't return the memory usage of a cluster. It results the amount of memory used by cluster services etc. (effective memory usage) . Effective memory is the amount of memory available for virtual machines.
Effective Memory = Aggregate host machine memory - (VMkernel memory + Service Console memory + other service memory)
Cluster memory usage should be calculated like this:
This doesn't return the memory usage of a cluster. It results the amount of memory used by cluster services etc. (effective memory usage) . Effective memory is the amount of memory available for virtual machines.
Cluster memory usage should be calculated like this:
as it's explained in https://www.vmware.com/support/developer/vc-sdk/visdk400pubs/ReferenceGuide/memory_counters.html
Could this be retrieved for cluster from root resource pool?
https://www.vmware.com/support/developer/vc-sdk/visdk25pubs/ReferenceGuide/vim.ResourcePool.html
And for last but not least thanks to dav for this great tool!