VCP-6 Objective 7.4–Troubleshoot and Monitor vSphere Performance

For this objective I used the following resources:

Objective 7.4 – Troubleshoot and Monitor vSphere Performance

Knowledge

Describe How Tasks and Events are Viewed in vCenter Server

View All Tasks

  • Log into the vSphere Web Client
  • Select the vCenter Server inventory object you want to view
    • To display the tasks for an object, select the object
    • To display the tasks in the vCenter Server, select the root folder
  • Select the Monitor tab
  • Select Tasks

The screenshot below shows the Tasks tab of a virtual machine in my lab:

Tasks

View Events

  • Log into the vSphere Web Client
  • Select the vCenter Server inventory object you want to view
    • To display the tasks for an object, select the object
    • To display the tasks in the vCenter Server, select the root folder
  • Select the Monitor tab
  • Select Events

The screenshot below shows the Events tab for my lab cluster:

Events

Identify Critical Performance Metrics

As you will see listed in the sections below, the critical points to monitor are CPU, memory, networking, and storage.

Explain Common Memory Metrics

Metric Description
SWR/s and SWW/s Measured in megabytes, these counters represent the rate at which the ESXi hosts is swapping memory in from disk (SWR/s) and swapping memory out to disk (SWW/s)
SWCUR This is the amount of swap space currently used by the virtual machine
SWTGT This is the amount of swap space that the host expects the virtual machine to use
MCTL Indicates whether the balloon driver is installed in the virtual machine
MCTLSZ Amount of physical memory that the balloon driver has reclaimed
MCTLTGT Maximum amount of memory that the host wants to reclaim via the balloon driver

 

Explain Common CPU Metrics

Metric Description
%Used Percentage of physical CPU time used  by a group of worlds
%RDY Percentage of time a group was ready to run but was not provided CPU resources
%CSTP Percentage of time the vCPUs of a virtual machine spent in the co-stopped state, waiting to be co-started
%SYS Percentage of time spent in the ESXi VMkernel on behalf of the world/resource pool

 

Explain Common Network Metrics

Metric Description
MbTX/s Amount of data transmitted in Mbps
MbRX/s Amount of data received in Mbps
%DRPTX Percentage of outbound packets dropped
%DRPRX Percentage of inbound packets dropped

 

Explain Common Storage Metrics

Metric Description
DAVG Average amount of time it takes a device to service a single I/O require (read or write)
KAVG The average amount of time it takes the VMkernel to service a disk operation
GAVG The total latency seen from the virtual machine when performing an I/O request
ABRT/s Number of commands aborted per second

 

Identify Host Power Management Policy

ESXi can take advantage of several power management features that the host hardware provides to adjust the trade-off between performance and power use. ESXi supports five different power management policies ranging from low performance/low power to high performance/high power. The table below provides a breakdown of the five policies:

Power Management Policy Description
Not Supported The host does not support any power management features or power management is not enabled in the system BIOS
High Performance The VMkernel detects certain power management features, but will not use them unless the system BIOS requests them for power capping or thermal events
Balanced (Default) The VMkernel uses the available power management features conservatively to reduce host energy consumption with minimal compromise to performance
Low Power The VMkernel aggressively uses available power management features to reduce host energy consumption at the risk of lower performance
Custom The VMkernel bases its power management policy on the values of several advanced configuration parameters. You can set these parameters in the vSphere Web Client Advanced Settings dialog box

To select a power management policy follow the below procedure:

    • Log into the vSphere Web Client with administrative privileges
    • From the Home screen select Host and Clusters
    • Expand your Datacenter and Cluster. Select the desired Host
    • In the right-hand navigation, select the Manage tab and select Settings
    • Scroll down and select Power Management, and click Edit
    • Select a power management policy for the host and click OK

Identify CPU/Memory Contention Issues

Monitor Performance Through ESXTOP

These two topics could easily fill pages of information. For quick and easy knowledge refer to the sections above outlining the more significant performance metrics to monitor. Read Section 7 of the vSphere Monitoring and Performance documentation as well as Duncan Epping’s esxtop blog and the VMware Communities document “Interpreting esxtop Statistics”. Also have a look at this YouTube video, VMworld 2010 – TA6720 Troubleshooting using ESXTOP for Advanced Users. While this video is a few years old, the concepts are still sound in using ESXTOP.

Troubleshoot Enhanced vMotion Compatibility (EVC) Issues

A quick primer on what Enhanced vMotion Compatibility is. EVC mode ensures that all ESX/ESXi hosts in a cluster present the same CPU level/feature set to virtual machines, even if the actual CPU’s on the host differ (they need to be of the same CPU manufacturer, you can not mix AMD with Intel and vise versa). With EVC mode enabled and configured it is then possible to leverage vMotion to migrate virtual machines across hosts.

For troubleshooting EVC mode, it mostly commands down to if the CPU in the ESXi host is supported. They below listing is pulled from VMware KB Article 1005764 – EVC and CPU Compatibility FAQ.

ESXi 6.0 Supports these EVC Modes

  • AMD Opteron Generation 1 (Rev. E)
  • AMD Opteron Generation 2 (Rev. F)
  • AMD Opteron Generation 3 (Greyhound)
  • AMD Opteron Generation 3 (no 3Dnow!)(Greyhound)
  • AMD Opteron Generation 4 (Bulldozer)
  • AMD Opteron “Piledriver” Generation
  • Intel “Merom” Generation (Intel Xeon Core 2)
  • Intel “Penryn” Generation (Intel Xeon 45nm Core2)
  • Intel “Nehalem” Generation (Intel Xeon Core i7)
  • Intel “Westmere” Generation (Intel Xeon 32nm Core i7)
  • Intel “Sandy Bridge” Generation
  • Intel “Ivy Bridge” Generation
  • Intel “Haswell” Generation

Compare and Contrast Overview and Advanced Charts

  • Overview Charts – Display multiple data sets in one panel to easily evaluate different resource statistics, display thumbnail charts for child objects, and display charts for a parent and a child object
  • Advanced Charts – Display more information than overview charts, are configurable, and can be printed or exported to a spreadsheet
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