Computation details for VMware metrics
Memory Pressure Index (MPI) takes into account consumed memory, active memory and other metrics like ballooning and swapping, and provides a realistic picture of the memory pressure in VMware Clusters, Hosts and VMs (Windows VMs only). MPI is computed for VMs only if there is an established relationship (GM_ASSOCIATED_TO_VN) between the VM and its corresponding Virtual Node (VN). To create this relationship, rerun the Virtual Node Linker system task (Administration > ETL & SYSTEM TASKS > System tasks > Virtual Node Linker).
MPI is used to compute Composite Memory Utilization and Composite Memory Consumption. Composite Memory Utilization and Composite Memory Consumption are alternate values for Memory Utilization and Consumed Memory computed using MPI.
The following tables elaborate computation and other important details for Memory Pressure Index (MPI):
MPI calculation for Clusters and Hosts
The following points about MPI for clusters and hosts, should be noted:
- MPI Value: MPI will have a value in the range of 0 – 100. Higher the number, higher the pressure.
- Minimum value: Minimum value of memory pressure = Active Memory Utilization
- Penalty points: There are penalty points for Consumed/Active Ratio, Ballooning, Over-commitment, and Swapping scenarios, and they are discussed in detail in the table that follows.
MPI Calculation for VMs (Windows only)
The following points about MPI for VMs, should be noted:
- MPI value: MPI will have a value in the range of 0 – 100. Higher the number, higher the pressure.
- Minimum value: Minimum value of memory pressure = Memory Utilization/2.
- Penalty points: Penalty is calculated based on the value of memory swap rate.
Metrics/Parameters Used in MPI Calculation
Composite Memory computation
Composite Memory is stored as an Indicator and is calculated through the following formula:
VMware - CPU Pressure Index
CPU Utilization of the cluster or host, reported by VMware, provides the overall CPU consumption of the cluster or host, but will not reflect any problems with capacity or performance of individual VMs.
CPU Pressure Index (CPI) uses CPU Ready of the VMs in addition to the CPU Utilization to present a better picture of CPU contention in the cluster or host. It is an index between 0 and 100. Higher the value, higher the pressure. This metric is calculated for VMware hosts and clusters.
The following points about CPI should be noted:
- CPI Value: CPU Pressure has a value in the range of 0 – 100. Higher the number, higher the pressure.
- Minimum value: Minimum value of CPU pressure = CPU Utilization
- Penalty Points: There are Penalty Points for Cluster CPU Ready Time and Cluster CPU Ready Exceed Count scenarios and they are elaborated in the table that follows.
The following table elaborates computation and other important details for CPU Pressure Index (CPI):
VMware - Storage Pressure Index
An index between 0 and 100, calculated using Storage utilization and Datastore I/O latency. Higher the value, higher the pressure. This metric is calculated for vSphere hosts and clusters.
The following points about SPI should be noted:
- SPI Value: Storage Pressure Index will have a value in the range of 0 – 100. Higher the number, higher the pressure.
- Minimum value: Minimum value of Storage pressure = Storage Utilization
- Penalty Points: There are Penalty Points for High I/O Latency Time scenarios and they are elaborated in the table that follows.
The following table elaborates computation and other important details for Storage Pressure Index (SPI):