VMware Communities: High Host Memory Usage on some VMs

VMware Communities: High Host Memory Usage on some VMs


Remember that host memory and guest memory are different. When a guest allocates memory , the host takes memory and gives it to the vm. As a guest uses and stops using that memory, it does not mark the memory as "no longer in use", so ESX can not reclaim it, so by default, the host memory usage will steadily go higher and higher, up to the max allocated to a vm, plus some overhead. This will remain that way until the vm is restarted, or if there is memory contention in the ESX host, at which time ballooning will kick in to reclaim some memory.


-KjB
VMware vExpert