Windows Memory – VM Test

To understand the metrics reported by this test, it is essential to understand how memory is handled by the operating system. On any Windows system, memory is partitioned into a part that is available for user processes, and another that is available to the OS kernel. The kernel memory area is divided into several parts, with the two major parts (called "pools") being a non-paged pool and a paged pool. The nonpaged pool is a section of memory that cannot, under any circumstances, be paged to disk. The paged pool is a section of memory that can be paged to disk. (Just being stored in the paged pool doesn't necessarily mean that something has been paged to disk. It just means that it has either been paged to disk or it could be paged to disk.) Sandwiched directly in between the nonpaged and paged pools (although technically part of the nonpaged pool) is a section of memory called the "System Page Table Entries," or "System PTEs." The WindowsMemory – VM test tracks critical metrics corresponding to the System PTEs and the pool areas of kernel memory of a Windows virtual machine.

Target of the test : Oracle VM Server

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each powered-on Windows VM on the Oracle VM Server being monitored.

Configurable parameters for the test
Parameters Description

Test Period

How often should the test be executed.

Host

The host for which the test is to be configured.

Port

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

Oracle VM Manager, Oracle VM Manager User, Oracle VM Manager Password, and Confirm Password

This test remotely connects to the Oracle VM Manager that manages the monitored Oracle VM Server and uses the web services API of the Oracle VM Manager to pull out metrics of interest. To enable this test to communicate with the web services API, you first need to configure the test with the IP address or host name of the Oracle VM Manager. This can be done using the Oracle VM Manager text box. Then, you need to configure the test with the credentials of a user with Admin rights to the Oracle VM Manager. Use the Oracle VM Manager User and Oracle VM Manager Password parameters to configure these credentials. Finally, confirm the password by retyping it in the Confirm Password text box.

SSL

By default, the Oracle VM Manager is SSL-enabled. Accordingly, the SSL flag is set to Yes by default. This indicates that the eG agent will communicate with the Oracle VM Manager via HTTPS by default.

WebPort

By default,, the Oracle VM Manager listens on 7002. This implies that while monitoring an Oracle VM server via an SSL-enabled Oracle VM Manager, the eG agent, by default, connects to port 7002 of the Oracle VM Manager to pull out metrics. In some environments however, this default port may not apply. In such a case, against the WebPort parameter, you can specify the exact port at which the Oracle VM Manager in your environment listens so that the eG agent communicates with that port.

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 VMs text 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 Oracle 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 an Oracle VM server 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.

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 (Windows) on every Windows VM; this VM agent allows the eG agent to collect “inside view” metrics from the Windows VMs without domain administrator rights. 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.

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.

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 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.
  • 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.
  • 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 the Monitoring VMware Infrastructures document.

  • 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.
  • 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.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Free entries in system page table

Indicates the number of page table entries not currently in use by the guest.

Number

The  maximum number of System PTEs that a server can have is set when the server boots. In heavily-used servers, you can run out of system PTEs. You can use the registry to increase the number of system PTEs, but that encroaches into the paged pool area, and you could run out of paged pool memory. Running out of either one is bad, and the goal should be to tune your server so that you run out of both at the exact same time. Typically, the value of this metric should be above 3000.

Page read rate in VM

Indicates the average number of times per second the disk was read to resolve hard fault paging.

Reads/Sec

 

Page write rate in VM

Indicates the average number of times per second the pages are written to disk to free up the physical memory.

Writes/Sec

 

Page input rate in VM

Indicates the number of times per second that a process needed to access apiece of memory that was not in its working set, meaning that the guest had to retrieve it from the page file.

Pages/Sec

 

Page output rate in VM

Indicates the number of times per second the guest decided to trim a process's working set  by writing some memory to disk in order to free up physical memory for another process.

Pages/Sec

This value is a critical measure of the memory utilization on a guest. If this value never increases, then there is sufficient memory in the guest. Instantaneous spikes of this value are acceptable, but if the value itself starts to rise over time or with load, it implies  that there is a memory shortage on the guest.

Memory pool non-paged data in VM

Indicates the total size of the kernel memory nonpaged pool.

MB

The kernel memory nonpage pool is an area of guest memory (that is, memory used by the guest operating system) for kernel objects that cannot be written to disk, but must remain in memory as long as the objects are allocated. Typically, there should be no more than 100 MB of non-paged pool memory being used.

Memory pool paged data in VM

Indicates the total size of the Paged Pool.

MB

If the Paged Pool starts to run out of space (when it's 80% full by default), the guest will automatically take some memory away from the System File Cache and give it to the Paged Pool. This makes the System File Cache smaller. However, the system file cache is critical, and so it will never reach zero. Hence, a significant increase in the paged pool size is a problem. This metric is a useful indicator of memory leaks in a guest. A memory leak occurs when the guest allocates more memory to a process than the process gives back to the pool. Any time of process can cause a memory leak. If the amount of paged pool data keeps increasing even though the workload on the guest remains constant, it is an indicator of a memory leak.