Understanding VMware Resource Pools

Because I use the system is English version, screenshots are also in English, so the text of the expression will often mixed in English, just for their convenience, but also please forgive me.

For ease of description, the resource pool (Resource pool) In this article is abbreviated to RP. vm= virtual machine, shares= share, vcpu= virtual machine cpu,limit= limit or upper limit, reservation= reserve.

Resource pools (Resource pool, RP) have 2 kinds, CPU resource pools and memory resource pools. The concept is easy to understand.

The following image is intercepted from the official "vsphere Resource Management Guide" page 36th

Figure 1: Resource pool

1 of these hosts have 6GHz CPU resources and 3GB of available memory resources. and created 2 resource pools, Rp-qa 2/3 of the resources, namely 4GHZ CPU resources and 2GB memory resources. Rp-marketing gets the remaining 1/3 of the resources.

A cluster (Cluster) resource pool contains the sum of resources for all hosts (host) in the cluster. For example, a cluster of 2 hosts, each host has 16GHz CPU and 16GB memory, then this cluster of resources is the sum of 32GHz CPU and 32GB memory. The pool of resources created in this cluster is allocated from this total available resource.

The cluster's available resources are always less than the total resources of the cluster, because each host consumes a portion of the CPU and memory resources and is reserved for its own hypervisor and cos (if it is ESX).

Although the cluster resource pool is the sum of all the host resources, it does not mean that a VM can use more resources than a single host. For example, 2 16GB memory hosts are clustered, a pool of 30GB memory is created in the cluster, but no single VM can use more than 16GB pram, because VMS cannot use resources across hosts, and the resources available to VMS are also affected by the upper limit on the physical resources of a single host.

?	Study Questions 1: Is this description correct? Because the VM cannot use resources across hosts, 1 of 20GB memory VMs will not be created in the above example in a resource pool of 30GB memory because 20GB is larger than the physical memory of a single host. (The answer point here)

Like VMS, resource pools have shares, reservation, and limit 3 configuration items. (see chart below)

Figure 2: Editing resource pool Properties