Hitachi

JP1 Version 12 JP1/Performance Management - Remote Monitor for Virtual Machine Description, User's Guide and Reference


1.6.4 Monitoring the memory resource

This subsection explains how to monitor the memory resource of a KVM system.

Organization of this subsection

(1) Overview

In a KVM system, the physical server's memory resource is allocated to multiple virtual machines. The OS running on a virtual machine recognizes its allocated memory resource as a normal physical memory.

If the combined total of the memory resources required by all the virtual machines exceeds the memory resources on the physical server, performance of the virtual machines will be affected adversely. Monitoring memory performance enables you to detect such performance deteriorations in the virtual machines.

The following two records are used to monitor memory resources. For details about records, see 5. Records.

  1. PI_HMI record

    This record is used to monitor the usage of physical memory by the virtual machine monitor and by each virtual machine.

  2. PI_VMI record

    This record is used to monitor the amount of memory resources allocated to each virtual machine.

The following figure shows the range of performance data collected in the PI_HMI and PI_VMI records.

Figure 1‒58: Correspondence between records and data collection ranges

[Figure]

(2) Monitoring examples

This subsection uses an example of monitoring a physical server on which a virtual environment is running to explain the factors that cause insufficient memory resources and how to solve such problems. The following figure shows the items monitored here and the flow of actions to take.

Figure 1‒59: Monitored items and flow of actions

[Figure]

(a) Example of monitoring the total memory usage of a physical server

You can monitor the total memory usage of a physical server in the Total Used % field of the PI_HMI record. If this value is large, the memory resources of the physical server are considered insufficient. Note that you can monitor this item by using an alarm that is provided in the monitoring template. The figure below shows a monitoring example.

Figure 1‒60: Example of monitoring the total memory usage

[Figure]

Monitoring template report to be checked

Host Memory Used

Monitoring template alarm to be checked

Host Memory Usage

In this example, the Total Used % value, which indicates the total of the Used %, VM Swap Used %, and Host Swap Used % values, exceeds 100%. Therefore, it is likely the memory resources for physical servers are insufficient.

In such a case, revise the configuration information for the virtual machines. If the total memory usage value does not improve even after the configuration information has been revised, consider either adding memory resources to the physical server or adding a physical server.