Home > Blogs > VMware VROOM! Blog > Tag Archives: Resource pool

Tag Archives: Resource pool

DRS Entitlement Viewer

Ever wondered how DRS distributes resources to VMs? How much resources your VMs are entitled to? How reservations, limits, and shares (RLS) affect your VMs’ resource availability? Our new fling, DRS Entitlement Viewer, is the answer.

DRS Entitlement Viewer is installed as a plugin to the vSphere Client. It is currently only supported for the HTML5-based vSphere Client. Once installed, it gives the hierarchical view of vCenter DRS cluster inventory with entitled CPU and memory resources for each resource pool and VM in the cluster.

Entitled resources can change with VMs’ resource demand and with the VM’s and resource pool’s RLS settings. So, users can get the current entitlements based on the VMs’ current demands and RLS settings of the VMs and resource pools.

DRS Entitlement Viewer also provides three different what-if scenarios:

  1. Changing RLS settings of a VM and/or resource pool
  2. What-if all the VMs’ resource demand is at 100%
  3. Both 1 and 2 happen together

Users can pick one of the three scenarios and can get new entitlements without actually changing RLS settings on the cluster.

Finally, DRS Entitlement Viewer also provides an option to export the new RLS values from a what-if scenario as a vSphere PowerCLI command that customers can execute against their vCenter to apply the new settings.

 

Expandable Reservation for Resource Pools

One of the questions I was often asked about resource pools (RP) is ‘Expandable reservation’. What is expandable reservation, and why should I care about it? Although it sounds intuitive, it can be easily misunderstood.

To put it simply, a resource pool with ‘expandable reservation’ can expand its reservation by asking more resources from its parent .

The need to expand reservation comes from the increase in reservation demand of its child objects (VMs or resource pools). If the parent resource pool is short of resources, then the parent expands it reservation asking resources from the grand parent.

Let us try to understand this with a simple example. Consider the following RP hierarchy. If RP-4 has to expand its reservation, it requests resources from its parent RP-3 and if RP-3 has to expand resources it eventually requests Root-RP.

exp-res-7

Continue reading