Compare this to the 640 shares each single VM gets in my current config (VM-* each have 64MB RAM, so a very low share value per VM). The ‘Normal’ shares value for memory on a resource pool is 163840. The single VM (MoveVM1) in ResourcePool2 gets 21% of the shares all to itself – much larger than the remaining VM’s in the Cluster, even though it may not be a VM of higher importance in your environment. That means that the VM’s in this ‘Normal’ pool actually get a bit more CPU time under resource contention than those in the parent cluster pool. If we divide the 21% shares by the 4 VM’s in ResourcePool1, we find that each VM gets 5.25% of the cluster’s total shares. If we look at the ‘Resource Allocation’ tab of the Cluster, we see that the VM’s in the Cluster resource pool each have 5% of the Shares for CPU, and each ‘Normal’ resource pool has 21% of the total shares of the cluster. The VM’s are all the same size as far as vRAM and vCPU are concerned. The resource pools are set to ‘Normal Shares’ with no other configuration changes to the default. I have 16 VM’s total, 4 in ResourcePool1, and 1 VM in ResourcePool2. Now, consider the following screen shot of the environment running on my laptop lab: The values on Resource Pools and individual VM’s combined can do funny things. Shares, Reservations, and Limits can also be set on a per-VM basis. Resource Pools can be used to apply resource Shares to VM’s, as well as Reservations and Limits.If the host/cluster has spare resources available for a guest it allocates availability of those resources based on the configured vRAM size and vCPU count, taking into consideration any limits (Mem/CPU) on the VM.
Vmware esxi 6.7 resource pool plus#
DRS is available in vSphere Enterprise and Enterprise Plus editions.
Resource Pools can only be used when VMware Distributed Resource Scheduler (DRS) is enabled on a cluster.I thought that I might try to explain the resource pool piece a bit better, particularly around Shares.įirst, a few technical points to remember: I recently found an example of an incorrect implementation of Resource Pools being used to organize VM’s in vCenter’s Hosts and Clusters view, without considering the potential performance impact of this configuration. I have found VMware vSphere Resource Pools to be an often misunderstood element, and incorrectly implemented by even seasoned VMware administrators.