Page File - VM Test

When the load imposed by applications and services running on a VM nears the amount of RAM allocated for the VM, additional storage is necessary. The page file serves as the temporary store on disk for memory that cannot be accommodated in the physical RAM. Since it is frequently accessed for storing and retrieving data that is needed for virtual memory access by application, the location and sizing of the page files can have a critical impact on VM's performance. Ideally, the server operating system and the page file should be available on different drives for optimal performance. Splitting the page file across different drives can improve performance further. A rule of thumb in sizing the page file is to set the maximum size of the page file to 1.5 times the available RAM. While this works well for VMs with smaller physical memory, for other VMs, the optimal page file size has to be determined based on experience using the system and studying the typical workload. This test tracks the usage of each page file on the VMs.

Note:

This test is applicable only for Windows VMs.

This test is disabled by default. To enable the test, go to the enable / disable tests page using the menu sequence : Agents -> Tests -> Enable/Disable, pick KVM server as the desired Component type, set Performance as the Test type, choose the test from the disabled tests list, and click on the < button to move the test to the ENABLED TESTS list. Finally, click the Update button.

Target of the test : A KVM server

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each page file available on the KVM 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

The port at which the host listens. By default, this is NULL.

Exclude VMs

Administrators of some virtualized environments may not want to monitor some of their less-critical VMs - for instance, VM templates - both from 'outside' and from 'inside'. The eG agent in this case can be configured to completely exclude such VMs from its monitoring purview. To achieve this, provide a comma-separated list of VMs to be excluded from monitoring in the Exclude VMstext box. Instead of VMs, VM name patterns can also be provided here in a comma-separated list. For example, your Exclude VMs specification can be: *xp,*lin*,win*,vista. 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 VMs on a virtual host by default. By providing a comma-separated list of VMs/VM 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 VMs.

Ignore VMs Inside
View

Administrators of some high security VMware environments might not have permissions to internally monitor one/more VMs. 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 VM names, or VM name patterns, for which the inside view need not be obtained. For instance, your Ignore VMs Inside View specification can be: *xp,*lin*,win*,vista. 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 VMs on a KVM host by default.

Note:

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

Ignore WINNT

By default, the eG agent does not support the inside view for VMs executing on Windows NT operating systems. Accordingly, the Ignore WINNT flag is set to Yes by default.

Inside View using

By default, this test communicates with every VM remotely and extracts “inside view” metrics. Therefore, by default, the Inside View Using flag is set to Remote connection to VM (Windows).

Typically, to establish this remote connection with Windows VMs in particular, eG Enterprise requires that the eG agent be configured with domain administrator privileges. In high-security environments, where the IT staff might have reservations about exposing the credentials of their domain administrators, this approach to extracting “inside view” metrics might not be preferred. In such environments therefore, eG Enterprise provides administrators the option to deploy a piece of software called the eG VM Agent on every Windows VM; this VM agent allows the eG agent to collect “inside view” metrics from the Windows VMs without domain administrator rights. Refer to Configuring the Remote Agent to Obtain the Inside View of Windows VMs, using the eG VM Agent for more details on the eG VM Agent. To ensure that the “inside view” of Windows VMs is obtained using the eG VM Agent, set the Inside View Using flag to eG VM Agent (Windows). Once this is done, you can set the Domain, Admin User, and Admin Password parameters to none.

Domain, Admin User, Admin Password, and Confirm Password

By default, this test connects to each virtual guest remotely and attempts to collect “inside view” metrics. In order to obtain a remote connection, the test must be configured with user privileges that allow remote communication with the virtual guests. The first step towards this is to specify the Domain within which the virtual guests reside. The Admin User and Admin Password will change according to the Domain specification. Discussed below are the different values that the Domain parameter can take, and how they impact the Admin User and Admin Password specifications:

  • If the VMs belong to a single domain:  If the guests belong to a specific domain, then specify the name of that domain against the Domain parameter. In this case, any administrative user in that domain will have remote access to all the virtual guests. Therefore, an administrator account in the given domain can be provided in the Admin User field and the corresponding password in the Admin Password field. Confirm the password by retyping it in the Confirm Password text box.
  • If the guests do not belong to any domain (as in the case of Linux/Solaris guests):  In this case, specify "none" in the Domain field, and specify a local administrator account name in the Admin User below.

    Prior to this, you need to ensure that the same local administrator account is available or is explicitly created on each of the virtual machines to be monitored. Then, proceed to provide the password of the Admin User against Admin Password, and confirm the password by retyping it in the Confirm Password text box.

    If key-based authentication is implemented between the eG agent and the SSH daemon of a Linux guest, then, in the Admin User text box, enter the name of the user whose <USER_HOME_DIR> (on that Linux guest) contains a .ssh directory with the public key file named authorized_keys. The Admin Password in this case will be the passphrase of the public key; the default public key file that is bundled with the eG agent takes the password eginnovations. Specify this as the Admin Password if you are using the default private/public key pair that is bundled with the eG agent to implement key-based authentication. On the other hand, if you are generating a new public/private key pair for this purpose, then use the passphrase that you provide while generating the pair. For the detailed procedure on Implementing Key-based Authentication refer to Troubleshooting the Failure of the eG Remote Agent to Connect to or Report Measures for Linux Guests.

  • If the guests belong to different domains: In this case, you might want to provide multiple domain names. If this is done, then, to access the guests in every configured domain, the test should be configured with the required user privileges; this implies that along with multiple Domain names, multiple Admin User names and Admin Passwords would also have to be provided. To help administrators provide these user details quickly and easily, the eG administrative interface embeds a special configuration page. To access this page, simply click on the Click here hyperlink that appears just above the parameters of this test in the test configuration page. To know how to use the special page, refer to Page File - VM Test.
  • If the Inside View Using flag is set to ‘eG VM Agent (Windows)’: In this case, the inside view can be obtained without domain administrator privileges. Therefore, set the Domain, Admin User, and Admin Password parameters to none.

Report By User

For the KVM server monitoring model, the Report By User flag is set to No by default, indicating that by default, the guest operating systems on the KVM server are identified using the hostname specified in the operating system. On the other hand, while monitoring KVM VDI environments, this flag is set to Yes by default; this implies that in case of VDI servers, by default, the guests will be identified using the login of the user who is accessing the guest OS. In other words, in VDI environments, this test will, by default, report measures for every username_on_virtualmachinename.

Report Powered OS

This flag becomes relevant only if the Report By User flag is set to ‘Yes’.

If the Report Powered OS flag is set to Yes (which is the default setting), then this test will report measures for even those VMs that do not have any users logged in currently. Such guests will be identified by their virtualmachine name and not by the username_on_virtualmachinename. On the other hand, if the Report Powered OS flag is set to No, then this test will not report measures for those VMs to which no users are logged in currently.

ReportTotal

Set the ReportTotal flag to Yes if you want the test to report total page file usage - i.e., the aggregate usage across multiple page files. In this case therefore, a Total descriptor will newly appear for this test in the eG monitoring console.

ReportTotalOnly

If both the ReportTotal and ReportTotalOnly flags are set to Yes, then the test will report only the aggregate usage across multiple page files - in other words, the test will report values for the Total descriptor only. Likewise, if the ReportTotal flag is set to No, and the ReportTotalOnly flag is set to Yes, then again, the test will report current usage for the Total descriptor only. However, if both the ReportTotal and ReportTotalOnly flags are set to No, then the test will report individual usages only. Also, if the flag is set to Yes and the ReportTotalOnly flag is set to No, then both the individual and Total usages will be reported.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Current usage

Indicates the current usage of this page file.

Percent

This metric should be less than 90%. If the page file does not have additional space, additional users/processes cannot be supported and system performance will suffer. To improve performance, consider resizing the page file. Microsoft Windows allows a minimum and maximum size of the page file to be specified. If the system has sufficient disk space, consider setting the page file to start out at the maximum size (by using the same value for the minimum and maximum sizes), so that system resources are not spent growing the page file size when there is a virtual memory shortage.