6.7

Table Of Contents
When considering cluster validity scenarios, you should understand these terms.
Reservation A fixed, guaranteed allocation for the resource pool input by the user.
Reservation Used The sum of the reservation or reservation used (whichever is larger) for
each child resource pool, added recursively.
Unreserved This nonnegative number differs according to resource pool type.
n
Nonexpandable resource pools: Reservation minus reservation used.
n
Expandable resource pools: (Reservation minus reservation used) plus
any unreserved resources that can be borrowed from its ancestor
resource pools.
Valid DRS Clusters
A valid cluster has enough resources to meet all reservations and to support all running virtual machines.
The following figure shows an example of a valid cluster with fixed resource pools and how its CPU and
memory resources are computed.
Figure 121. Valid Cluster with Fixed Resource Pools
cluster
Total Capacity: 12G
Reserved Capacity: 11G
Available Capacity: 1G
RP1
Reservation: 4G
Reservation Used: 4G
Unreserved: 0G
RP2
Reservation: 4G
Reservation Used: 3G
Unreserved: 1G
RP3
Reservation: 3G
Reservation Used: 3G
Unreserved: 0G
VM1, 2G
VM7, 2G
VM2, 2G
VM4, 1G VM8, 2G
VM3, 3G VM5, 2GVM6, 2G
The cluster has the following characteristics:
n
A cluster with total resources of 12GHz.
n
Three resource pools, each of type Fixed (Expandable Reservation is not selected).
n
The total reservation of the three resource pools combined is 11GHz (4+4+3 GHz). The total is shown
in the Reserved Capacity field for the cluster.
vSphere Resource Management
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