VCP 4 prep objective 7.3 – Create and Configure resource pools

Objective 7.3 – Create and Configure resource pools

Determine resource pool requirements for a given situation

Resource pools should be used manage resource for groups of virtual machines independent of the hardware but they can be used to delegate privileges, organise virtual machines etc.

Evaluate appropriate shares, reservations and limits in a given situation

Specifying limits for a resource pool which is a child of another resource pool will allow you to predict the behaviour reliably i.e. you know that if an expandable reservation exists then the limit will stop it comsuming more than you have specified.

Shares allow you to divvy up resource on a ratio basis should resources become contended.

Reservations allow you to specify a minimum amount of resource available for an resource pool.

Evaluate virtual machines for a given resource pool

The resource allocation tab will give you a view into the resource usage of that particular resource pool and the summary tab also provides swapping, ballooning and shared memory usage.

set CPU resource shares / reservations / limits

  • Reservation – total MHz reserved for that resource pool
  • Limits – total MHz that resource pool, generally defined when an expandable reservation is in place
  • Shares – gives priority to virtual machines with a higher number of shares when resources are contended. 

set memory resource shares / reservations / limits

  • Reservation – total ESX RAM reserved for the resource pool i.e. physical RAM; note that memory virtualisation overhead counts against the reservation too.
  • Limits – total ESX RAM that can be comsumed by the resource pool.
  • Shares – gives priority to virtual machines with a higher number of shares when resources are contended.

Define expandable reservation

Expandable reservations allow child resource pools to use a parent resource pools available resources. It is not guaranteed though and is purely a first come first served basis. The rsource pool can be limited with a expandable reservation; this limits how much the child resource pool can request.

add virtual machines to resource pool

Note when adding virtual machines to a resource pool that explicitly defined limits and reservations will be kept. Explicitly defined shares will be adjusted as a percentage of the resource pool; if the percentage will be extremely low or extremely high then a warning will be issued.

describe resource pool hierarchy

Resource pool hierarchy is as follows:

Parent resource pools are: ESX/ESXi hosts or DRS Clusters. An administrator can create a resource pool but that will be a child of one of the previously stated parents but it could be a parent of another resource pool created by an administator.

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