Monitoring the performance of Azure Virtual Machine Hosts

Guest Metrics

Use the following metrics to monitor your virtual machine guest operating system performance.

Microsoft Windows

You can use the following metrics to monitor the processor activity and memory if you are using a Windows Virtual Machine. 

Azure VM Processor Information (PAF_Processor_Information)

Percent User Time

This attribute reports the percentage of elapsed time the processor spends in the user mode. User mode is a restricted processing mode designed for applications, environment subsystems, and integral subsystems.

Percent Privileged Time

This attribute reports the percentage of elapsed time that the process threads spent executing code in privileged mode. When a Windows system service is called, the service will often run in privileged mode to gain access to system-private data.

Such data is protected from access by threads executing in user mode. Calls to the system can be explicit or implicit, such as page faults or interrupts. Unlike some early operating systems, Windows uses process boundaries for subsystem protection in addition to the traditional protection of user and privileged modes. Some work done by Windows on behalf of the application might appear in other subsystem processes in addition to the privileged time in the process.

Azure VM Memory (PAF_Memory)

When monitoring virtual machines it is important to monitor the impact of free and available memory on the performance of virtual machines. Use the following metrics to monitor your VM memory. 

Available Bytes

This attribute measures the amount of memory available on the computer in Megabytes. A low memory indicates that you might soon run out of memory resulting in critical performance issues. The virtual machine might stop responding in such scenarios if the available memory is too less to accommodate data. A fair amount of free memory indicates that you can add more data on the virtual machines, thereby distributing the load from other virtual machines. 

Set threshold on this attribute to get notified about the memory available on the host in MB. Consider setting up an alert to trigger if the available memory is less than 20 percent or more than 60 percent.

Committed Bytes In Use

Committed Bytes is the amount of committed virtual memory, in bytes. Committed memory is the physical memory which has space reserved on the disk paging file(s). If this value is constantly increasing without leveling off, you might need to investigate. 

Red Hat Enterprise Linux

You can use the following metrics to monitor the processor activity and memory if you are using a Linux Virtual Machine. 

Azure VM Processor (PAF_Processor)

Processor Time

This attribute reports the percentage of time the processor was busy during the sampling interval. 

IO Wait Time

This attribute reports the percentage of time processor waits for IO in Linux virtual machines. 

Azure VM Memory

When monitoring virtual machines it is important to monitor the impact of free and available memory on the performance of virtual machines. Use the following metrics to monitor your VM memory. 

Percent Available Memory

Reports the available memory in percent on Linux virtual machines. A low memory indicates that you might soon run out of memory resulting in critical performance issues. The virtual machine might stop responding in such scenarios if the available memory is too less to accommodate data. A fair amount of free memory indicates that you can add more data on the virtual machines, thereby distributing the load from other virtual machines. 

Set threshold on this attribute to get notified about the memory available on the host in MB. Consider setting up an alert to trigger if the available memory is less than 20 percent or more than 60 percent.

Percent Used Memory

Reports the used memory in percentage on Linux virtual machines. You can use this metric in combination with the Percent Available Memory. 

Host Metrics

Use the following metrics to monitor your Virtual Machine host. 

Percentage CPU

This attribute displays the percentage of allocated CPU that is currently in use by the virtual machine(s). High CPU utilization is good if all your work is being done as expected. Low CPU utilization is normal when the CPU has a light load. If your system always seems to be running above 95% utilization and you have done everything you can to improve your system's performance, then you may want to alter or deactivate the default range thresholds to avoid false alarms.

CPU Credits Consumed

This attribute displays the total number of credits consumed by the virtual machine. This metric can be used in a combination with the CPU Credits Remaining attribute that displays the total number of credits available to the burst. CPU credits are accumulated when the CPU is not fully utilized. These credits can be used when there is a need of CPU.