Using resource pool guidelines
ESXi provides several mechanisms to configure and adjust the allocation of CPU and memory resources to VMs. Thus, resource management configurations have a significant impact on VM performance.
If you expect flexibility in the total available resources, then use shares, not reservations. It will allocate resources fairly across the VMs. Even if you upgrade your hardware, each VM will stay at the same relative priority, using shares. The relative priority remains the same even though each share represents a larger amount of memory or CPU.
Remember that shares will only be effective in the case of resource contention. So, if you think you can have an immediate effect on the resources of a VM by increasing the number of shares, you are mistaken. Share values are used in order to determine the dynamic entitlement of a VM. Dynamic entitlement is used in order to determine fairness and also opportunistically distribute unused resources. Therefore, while shares are...
