I've been managing Vmware environments for a long time (since 2.5), but have always been fortunate to operate in a RAM-rich environment. I'm having my first experience with a host that is nearly out of RAM. I'm not sure if I should be concerned or not, as I have some confusion about active vs consumed vs host usage. (This is a ESXi 5.5 host if that is relevant)
My immediate concern is a host memory usage indicator showing near 100%. In looking at my RAM counter, it appears that host memory usage is essentially equal to adding up all the RAM I have assigned the VMs on this host. However, I know for a fact (and it would be very unlikely anyway) that these VMs are not using 100% RAM inside the guest OS. Looking at the active memory counter, I am only showing about 20% of my total consumed memory and 0 ballooning at the host level. I also have very few memory reservations. Only about 10% reserved and the rest show 0 for the reservation as I wanted Vmware to work it's scheduling magic.
So with that in mind, do I have anything to worry about with memory utilization being so high? I know from training that Vmware allows memory over provisioning, but if host usage = assigned guest RAM when I am this close to 100%, I am a bit puzzled. When does it start reclaiming inactive RAM for other VMs?
Thanks for any advice and information.
Is this host running in a cluster or standalone?
Check memory Swap in and Swap out graph on the host. You will notice the swap going up frequently if there is a memory contention on the host.
Ensure that you have VMware tools installed on the host, it will allow the host to reclaim the unused memory.