Disk Activity - VM Test

This test reports statistics pertaining to the input/output utilization of each physical disk on a VM.

Target of the test : A Nutanix Acropolis server

Agent deploying the test : A remote agent

Outputs of the test : One set of results for every combination of virtual_guest:disk_partition or guest_user:disk_partition.

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

  4. Prism IP - If the eG manager had discovered the target Nutanix Acropolis server by connecting to the Nutanix Prism, then the IP address of the Nutanix Prism server used for discovering this Nutanix Acropolis server would be automatically displayed against the prism ip parameter; similarly, the prism user and prism password text boxes will be automatically populated with the Prism user credentials, using which Nutanix Acropolis discovery was performed.

     

    If this Nutanix Acropolis server has not been discovered using the Nutanix Prism, but you still want to monitor the Nutanix Acropolis server via the Prism, then select the IP address of the Prism server that you wish to use for monitoring the Nutanix Acropolis server from the prism ip list. By default, this list is populated with the IP address of all Nutanix Prism hosts that were added to the eG Enterprise system at the time of discovery. Upon selection, the PRISM user and prism password that were pre-configured for that Nutanix Prism will be automatically displayed against the respective text boxes.

     

    On the other hand, if the IP address of the Prism server of interest to you is not available in the list, then, you can add the details of the Prism server on-the-fly, by selecting the Other option from the prism ip list. This will invoke the MANAGER DISCOVERY - VIRTUAL PLATFORM SETTINGS page. Refer to the Configuring eG Enterprise to Monitor Nutanix Acropolis topic for details on how to use this page.

  5. Prism user and prism password - If the eG manager had discovered the target Nutanix Acropolis server by connecting to the Nutanix Prism, then the IP address of the Nutanix Prism server used for discovering this Nutanix Acropolis server would be automatically displayed against the prism ip parameter; similarly, the prism user and prism password text boxes will be automatically populated with the Prism user credentials, using which Nutanix Acropolis discovery was performed.

     

    If this Nutanix Acropolis server has not been discovered using the Nutanix Prism, but you still want to monitor the Nutanix Acropolis server via the Prism, then select the IP address of the Prism server that you wish to use for monitoring the Nutanix Acropolis server from the prism ip list. By default, this list is populated with the IP address of all Nutanix Prism hosts that were added to the eG Enterprise system at the time of discovery. Upon selection, the PRISM user and prism password that were pre-configured for that Nutanix Prism will be automatically displayed against the respective text boxes.

    On the other hand, if the IP address of the Prism server of interest to you is not available in the list, then, you can add the details of the Prism server on-the-fly, by selecting the Other option from the prism ip list. This will invoke the MANAGER DISCOVERY - VIRTUAL PLATFORM SETTINGS page. Refer to the Configuring eG Enterprise to Monitor Nutanix Acropolis topic for details on how to use this page.

  6. confirm password - Confirm the password by retyping it here.

  7. ssl - By default, the Nutanix Prism server is SSL-enabled. Accordingly, the SSL flag is set to Yes by default. This indicates that the eG agent will communicate with the Prism server via HTTPS by default.

  8. webport - By default, the Nutanix Prism server listens on port 9440. This implies that while monitoring a Nutanix Acropolis server via the Prism server, the eG agent connects to port 9440.

  9. exclude vms - Administrators of some virtualized environments may not want to monitor some of their less-critical VMs 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.

  10. ignore vms inside view - Administrators of some high security Nutanixe 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 Nutanix Acropolis 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.

  11. 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.

  12. 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. Refer to Configuring the eG Agent to Collect Current Hardware Status Metrics 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.

  13. 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 Disk Activity - 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.
  14. REPORT BY USER - While monitoring a Nutanix Acropolis server, the REPORT BY USER flag is set to No by default, indicating that by default, the guest operating systems on the Acropolis server are identified using the hostname specified in the operating system. On the other hand, while monitoring Acropolis desktop 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.

  15. REPORT POWERED OS - This flag becomes relevant only if thereport by user flagis 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.      

  16. use sudo –This parameter is of significance to Linux and Solaris VMs only. By default, the USE SUDO parameter is set to No. This indicates that, by default, this test will report the detailed diagnosis for the Percent virtual disk busy measure of each disk partition being monitored by executing the /usr/bin/iotop command or /usr/sbin/iotop command. However, in some highly secure virtualized environments, this command cannot be executed directly on a Linux. In such cases, set this parameter to Yes. This will enable the eG agent to execute the sudo/usr/bin/iotop command or sudo/usr/sbin/iotop  and retrieve the detailed diagnosis of the Percent virtual disk busy measure.
  17. use iotop – The Disk Activity – VM test uses the iotop command to collect detailed diagnostics on disk activity from Linux VMs. By default, this flag is set to No, indicating that the test will not use the iotop command – this in turn implies that this test will not report detailed diagnostics for Linux VMs by default. If you want the test to report detailed metrics on disk activity on Linux VMs, set this flag to Yes.

  18. DD FREQUENCY - Refers to the frequency with which detailed diagnosis measures are to be generated for this test. For a Nutanix Acropolis server, this is set to 1:1 by default. This indicates that, by default, detailed measures will be generated every time this test runs, and also every time the test detects a problem.

  19. DETAILED DIAGNOSIS - To make diagnosis more efficient and accurate, the eG 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

Percent virtual disk busy:

Indicates the percentage of elapsed time during which the disk is busy processing requests (i.e., reads or writes).

Percent

Comparing the percentage of time that the different disks are busy, an administrator can determine whether load is properly balanced across the different disks.

Percent reads from virtual disk:

Indicates the percentage of elapsed time that the selected disk drive is busy servicing read requests.

Percent

 

Percent writes to virtual disk:

Indicates the percentage of elapsed time that the selected disk drive is busy servicing write requests.

Percent

 

Virtual disk read time:

Indicates the average time in seconds of a read of data from the disk.

Secs

 

Virtual disk write time:

Indicates the average time in seconds of a write of data from the disk.

Secs

 

Avg. queue for virtual disk:

Indicates the average number of both read and write requests that were queued for the selected disk during the sample interval.

Number

 

Current queue for virtual disk:

The number of requests outstanding on the disk at the time the performance data is collected.

Number

This measure includes requests in service at the time of the snapshot. This is an instantaneous length, not an average over the time interval. Multi-spindle disk devices can have multiple requests active at one time, but other concurrent requests are awaiting service. This counter might reflect a transitory high or low queue length, but if there is a sustained load on the disk drive, it is likely that this will be consistently high. Requests experience delays proportional to the length of this queue minus the number of spindles on the disks. This difference should average less than two for good performance.

Reads from virtual disk:

Indicates the number of reads happening on a logical disk per second.

Reads/Sec

A dramatic increase in this value may be indicative of an I/O bottleneck on the guest.

Data reads from virtual disk:

Indicates the rate at which bytes are transferred from the disk during read operations.

KB/Sec

A very high value indicates an I/O bottleneck on the guest.

Writes to virtual disk:

Indicates the number of writes happening on a local disk per second.

Writes/Sec

A dramatic increase in this value may be indicative of an I/O bottleneck on the guest.

Data writes to virtual disk:

Indicates the rate at which bytes are transferred from the disk during write operations.

KB/Sec

A very high value indicates an I/O bottleneck on the guest.

Disk service time:

Indicates the average time that this disk took to service each transfer request ( i.e., the average I/O operation time)

Secs

A sudden rise in the value of this measure can be attributed to a large amount of information being input or output. A consistent increase however, could indicate an I/O processing bottleneck.

Disk queue time:

Indicates the average time that transfer requests waited idly on queue for this disk.

Secs

Ideally, the value of this measure should be low.

Disk I/O time:

Indicates the average time taken for read and write operations of this disk.

Secs

The value of this measure is the sum of the values of the Disk service time and Disk queue time measures.

A consistent increase in the value of this measure could indicate a latency in I/O processing.

The detailed diagnosis of the Percent virtual disk busy measure, if enabled, provides information such as the Process IDs executing on the disk, the Process names, the rate at which I/O read and write requests were issued by each of the processes, and the rate at which data was read from and written into the disk by each of the processes. In the event of excessive disk activity, the details provided in the detailed diagnosis page will enable users to figure out which process is performing the I/O operation that is keeping the disk busy. The detailed diagnosis for this test is available for Windows guests only, and not Linux guests.

Figure 1 : The detailed diagnosis of the Percent virtual busy measure