Appendix D: Capacity Management : Capacity Monitoring and Establishing Triggers
Capacity Monitoring and Establishing Triggers
The metrics listed in the following table should be carefully monitored to warn of approaching or exceeding consumption thresholds. These metrics should be measured against each vCloud provider virtual datacenter and for each organization virtual datacenter within it. To monitor for threshold breaches, and possible subsequent violation of service level commitments to the vCloud consumer, the appropriate tools and triggers are needed for proper notification.
Table 11. Capacity Monitoring Metrics
Monitored per
Provider virtual datacenter, organization virtual datacenter
For the Pay As You Go allocation model this is the aggregation of reservations values for the contained virtual machines
Provider virtual datacenter, organization virtual datacenter
CPU utilization
Provider virtual datacenter, organization virtual datacenter
Memory utilization
Provider virtual datacenter, organization virtual datacenter
Datastore utilization
Provider virtual datacenter
Transfer store utilization
Network IP addresses available
Network IP addresses consumed
Network VLANs available
Network ephemeral ports consumed
vNetwork Distributed Switch
If thresholds are exceeded, the group responsible for capacity management of the vCloud should be notified to add additional capacity. Take into account the time required to add the physical components necessary to increase the capacity of a provider virtual datacenter. A vCloud-aware capacity management tool should be deployed. Whichever tool is chosen, the capacity model can be used to forecast new provider virtual datacenter capacity usage as well as ongoing capacity management of existing provider virtual datacenters. It should also account for expansion triggers based on provisioning timeframes.
After the total amount of available resources has been calculated for a provider virtual datacenter, no adjustments to that provider virtual datacenter (such as adding or removing hosts) should be made without updating the calculated value. This model can be altered if long-term CPU and memory reservations are not at the levels for which they were designed. An increase in the resources allocated to an organization virtual datacenter can affect the remaining capacity of a full provider virtual datacenter. Full provider virtual datacenters should be monitored on a weekly basis. The resource consumption of virtual machines within an organization’s virtual datacenter should be reviewed to identify trends that indicate the resources purchased are insufficient.
VMware vCenter CapacityIQ™, though not vCloud Director aware, can be used to provide insight into provider virtual datacenter utilization and trends.