Virtual machine "Uptime" metric in Performance charts resets after a vMotion

Products

• VMware vCenter Server

Issue/Introduction

• In the vSphere Client performance charts, the "Uptime" metric for a virtual machine resets to zero.
  
  
  
  
• This behavior is observed immediately after performing a vMotion or Storage vMotion on the affected virtual machine.
• No errors or events indicating an actual Guest OS reboot are recorded.

Cause

The "Uptime" metric displayed in the vCenter Server performance charts measures the uptime of the virtual machine process (vmx process) running on the ESXi host.
It does not reflect the actual continuous uptime of the Guest OS itself.
During a vMotion, the execution state of the virtual machine is transferred to a new vmx process.
Because a new vmx process is spawned, the uptime counter for the process is reset.

Resolution

This is expected behavior. 
It does not indicate the Guest OS restart and no action is required.