This is an advice by E4C Troubleshooter to remove limits on virtual machines.
Setting a limit on VM memory OR CPU directly is not the best thing to do. VM level reservation can be rather evil, it will hoard memory if it has been used by the virtual machine once. Even if the virtual machine becomes idle, the VMkernel will not reclaim this memory and return it to the free memory set. This means that ESX can start swapping and ballooning if no free memory is available for other virtual machines while the owning VM’s aren’t using their claimed reserved memory. It also has influence on the slot size of High availability.
Eco4Cloud suggests to rightsize VMs through E4C Troubleshooter and use limits on resource pools, avoiding resource limits as much as possible.
Posted in: VMware vSphere