Memory Usage Test

This test reports statistics related to the usage of the physical memory of the system.

Target of the test : Any host system

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every server being monitored

Configurable parameters for the test
  1. TEST PERIOD - How often should the test be executed
  2. Host - The host for which the test is to be configured
  3. useglance - This flag applies only to HP-UX systems. HP GlancePlus/UX is Hewlett-Packards’s online performance monitoring and diagnostic utility for HP-UX based computers. There are two user interfaces of GlancePlus/UX -- Glance is character-based, and gpm is motif-based. Each contains graphical and tabular displays that depict how primary system resources are being utilized. In environments where Glance is run, the eG agent can be configured to integrate with Glance to pull out detailed metrics pertaining to the memory usage of the HP-UX systems that are being monitored. By default, this integration is disabled. This is why the useglance flag is set to No by default. You can enable the integration by setting the flag to Yes. If this is done, then the test polls the Glance interface of HP GlancePlus/UX utility to report the detailed diagnosis information pertaining to memory usage.

  4. HIGH SECURITY - This flag is applicable only when the target Linux host is monitored in the agentless manner. In highly secure environments, eG Enterprise could not perform agentless monitoring on a Linux host using SSH. To enable monitoring of the Linux hosts in such environments, set the HIGH SECURITY flag to Yes. It indicates that eG Enteprise will connect to the target Linux host in a more secure way and collect performance metrics. By default, this flag is set to No.

  5. DETAILED DIAGNOSIS – To make diagnosis more efficient and accurate, the eG Enterprise suite embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

    The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

    • The eG manager license should allow the detailed diagnosis capability
    • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Total physical memory:

Indicates the total physical memory of the system.

MB

 

Used physical memory:

Indicates the used physical memory of the system.

MB

 

Free physical memory:

Memory that does not contain any valuable data, and that will be used first when processes, drivers or Operating System need more memory. This does not include standby memory.

MB

This measure typically indicates the amount of memory available for use by applications running on the target host.

On Unix operating systems (AIX and Linux), the operating system tends to use parts of the available memory for caching files, objects, etc. When applications require additional memory, this is released from the operating system cache. Hence, to understand the true free memory that is available to applications, the eG agent reports the sum of the free physical memory and the operating system cache memory size as the value of the Free physical memory measure while monitoring AIX and Linux operating systems. 

Physical memory utilized:

Indicates the percent usage of physical memory.

Percent

Ideally, the value of this measure should be low. While sporadic spikes in memory usage could be caused by one/more rogue processes on the system, a consistent increase in this value could be a cause for some serious concern, as it indicates a gradual, but steady erosion of valuable memory resources. If this unhealthy trend is not repaired soon, it could severely hamper system performance, causing anything from a slowdown to a complete system meltdown.

You can use the detailed diagnosis of this measure to figure out which processes on the host are consuming memory excessively.

Cached memory

This measure is an aggregate of Standby memory and Modified memory.

MB

 

Note:

While monitoring Linux/AIX operating systems, you may observe discrepancies between the value of the Physical memory utilized measure and the memory usage percentages reported per process by the detailed diagnosis of the same measure. This is because, while the Physical memory utilized measure takes into account the memory in the OS cache of the Linux/AIX operating system, the memory usage percent that the detailed diagnosis reports per process does not consider the OS cache memory.