Memory Usage - VM Test

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

Target of the test : An IBM pSeries server

Agent deploying the test : A remote agent

Outputs of the test : One set of results for every AIX LPAR on the target IBM pSeries server.

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed

Host

The IP address of the host for which this test is to be configured.

Port

Indicate the port at which the specified Host listens. By default, this is NULL.

Management Server, Management User, Management Password

This test connects to an HMC/IVM server to perform LPAR discovery and to collect host-level and "outside view" metrics from the pSeries server. To enable this communication, first, provide the IP address/host name of the HMC/IVM server in the Management Server text box. If the eG manager had automatically discovered the target pSeries server by connecting to an HMC server in the environment, then, the IP address/host name and user credentials pertaining to that HMC server will be automatically displayed in the Management Server, Management User, and Management Password text boxes.

However, if the pSeries server being monitored was manually added to the eG Enterprise system (and not auto-discovered via the HMC server), then, you will have to explicitly indicate whether the target pSeries server is managed by an HMC server or an IVM server by selecting an option from the Is Managed By list. If the HMC option is chosen, then, you will have to provide the IP address of the HMC server that manages the target pSeries server in the Management Server text box. In such a case, in the Management User and Management Password text boxes, you will have to provide the credentials of an HMC user who is assigned the hmcviewer role.

On the other hand, if the IVM option is chosen from the Is Managed By list, it implies that the IP address/host name and user credentials pertaining to that IVM server has to be explicitly provided in the Management Server, Management User, and Management Password text boxes.

Confirm Password

Confirm the HMC Password by retyping it here

Domain

Set the Domain parameter to none.

Admin User, Admin Password, Confirm Password

The eG agent remotely communicates with each discovered LPAR on the pSeries server to obtain their "inside view". For this, the eG agent will have to be configured with the credentials of a valid user with access rights to each LPAR. If a single user is authorized to access all the LPARs on the pSeries server, provide the name and password of the user in the Admin User and Admin Passsword text boxes, and confirm the password by retyping it in the Confirm Password text box. On the other hand, if the test needs to communicate with different LPARs using different user accounts, then, multiple user names and passwords will have to be provided. To help administrators provide these multiple user details quickly and easily, the eG administrative interface embeds a special configuration page. To know how to use this page, refer to Configuring Users for LPAR Monitoring.

SSL

By default, the HMC/IVM server (as the case may be) is not SSL-enabled. This indicates that by default, the eG agent communicates with the HMC/IVM server using HTTP. Accordingly, the SSL flag is set to No by default. If you configure the HMC/IVM server to use SSL, then make sure that the SSL flag is set to Yes, so that the eG agent communicates with the HMC/IVM server using HTTPS.

Ignore VMs Inside View

Administrators of some high security LPAR environments might not have permissions to internally monitor one/more LPARs. The eG agent can be configured to not obtain the 'inside view' of such ‘inaccessible’ VMs using the Ignore VMs Inside View parameter.  Against this parameter, you can provide a comma-separated list of LPAR names, or LPAR name patterns, for which the inside view need not be obtained. For instance, your Ignore VMs Inside View specification can be: *lp,aixlp*,lin*. Here, the * (asterisk) is used to denote leading and trailing spaces (as the case may be). By default, this parameter is set to none indicating that the eG agent obtains the inside view of all LPARs on a pSeries server by default.

Note:

While performing LPAR discovery, the eG agent will not discover the operating system of the LPARs configured in the Ignore VMs Inside View text box.

Exclude VMs

Administrators of some virtualized environments may not want to monitor some of their less-critical LPARs both from 'outside' and from 'inside'. The eG agent in this case can be configured to completely exclude such LPARs from its monitoring purview. To achieve this, provide a comma-separated list of LPARs to be excluded from monitoring in the Exclude VMs text box. Instead of LPARs, LPAR name patterns can also be provided here in a comma-separated list. For example, your Exclude VMs pecification can be: *lp,aixlp*,lin*. Here, the * (asterisk) is used to denote leading and trailing spaces (as the case may be). By default, this parameter is set to none indicating that the eG agent obtains the inside and outside views of all AIX LPARs on a virtual host by default. By providing a comma-separated list of LPARs/LPAR name patterns in the Exclude VMs text box, you can make sure the eG agent stops collecting 'inside' and 'outside' view metrics for a configured set of LPARs.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise 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 this LPAR.

MB

 

Used physical memory

Indicates the used physical memory of this LPAR.

MB

 

Free physical memory

Indicates the free physical memory of the LPAR.

MB

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

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 LPARs. 

Physical memory utilized

Indicates the percent usage of physical memory by this LPAR.

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 LPAR, 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 VM 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 VM are consuming memory excessively.

Available physical memory

Indicates the amount of physical memory, immediately available for allocation to a process or for system use.

MB

Not all of the Available physical memory is Free physical memory. Typically, Available physical memory is made up of the Standby List, Free List, and Zeroed List.

When Windows wants to trim a process' working set, the trimmed pages are moved (usually) to the Standby List. From here, they can be brought back to life in the working set with only a soft page fault (much faster than a hard fault, which would have to talk to the disk). If a page stays in the standby List for a long time, it gets freed and moved to the Free List.

In the background, there is a low priority thread (actually, the only thread with priority 0) which takes pages from the Free List and zeros them out. Because of this, there is usually very little in the Free List.

All new allocations always come from the Zeroed List, which is memory pages that have been overwritten with zeros. This is a standard part of the OS' cross-process security, to prevent any process ever seeing data from another. If the Zeroed List is empty, Free List memory is zeroed and used or, if that is empty too, Standby List memory is freed, zeroed, and used. It is because all three can be used with so little effort that they are all counted as "available".

A high value is typically desired for this measure.

This measure will be available for Windows 2008 VMs only.

Modified memory

Indicates the amount of memory that is allocated to the modified page list.

MB

This memory contains cached data and code that is not actively in use by processes, the system and the system cache. This memory needs to be written out before it will be available for allocation to a process or for system use.

Cache pages on the modified list have been altered in memory. No process has specifically asked for this data to be in memory, it is merely there as a consequence of caching. Therefore it can be written to disk at any time (not to the page file, but to its original file location) and reused. However, since this involves I/O, it is not considered to be Available physical memory.

This measure will be available for Windows 2008 VMs only.

Standby memory

Indicates the amount of memory assigned to the standby list.  

MB

This memory contains cached data and code that is not actively in use by processes, the system and the system cache. It is immediately available for allocation to a process or for system use. If the system runs out of available free and zero memory, memory on lower priority standby cache page lists will be repurposed before memory on higher priority standby cache page lists.

Typically, Standby memory is the aggregate of Standby Cache Core Bytes,Standby Cache Normal Priority Bytes, and Standby Cache Reserve Bytes. Standby Cache Core Bytes is the amount of physical memory, that is assigned to the core standby cache page lists. Standby Cache Normal Priority Bytes is the amount of physical memory, that is assigned to the normal priority standby cache page lists. Standby Cache Reserve Bytes is the amount of physical memory, that is assigned to the reserve standby cache page lists.

This measure will be available for Windows 2008 VMs only.

Cached memory

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

MB

This measure will be available for Windows 2008 VMs only.

Note:

While monitoring AIX LPARs, 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 AIX LPAR, the memory usage percent that the detailed diagnosis reports per process does not consider the OS cache memory.