What is vMotion?

• vMotion  enables live migration of a running virtual machine between ESXi Hosts
• It is transparent to the Virtual Machine’s OS and applications.
• Invaluable tool to admin to achieve the followings;
  • Avoid Server Downtime
  • Allow Troubleshooting
  • Provide Flexibility
• Key enabler of DRS, DPM, and FT

What needs to be migrated?

• Processor and devices state  – CPU, Network, SVGA
• Disk – Use shared storage between source and destination
• Memory – Pre copy memory while Virtual Machine is running

How vMotion Works?

• Quiesce Virtual Machine on source machine.
• Transfer memory and device state(checkpoint) from source to destination.
• Resume Virtual Machine on Destination
• Copy remainder of memory from source to destination
• Free Virtual Machine resources on source machine.

Other Interesting Facts, Problems, and Troubleshooting: –

• Virtual  Machine remains suspended during memory transfer
• Copying Virtual Machine with large memory size may problematic.
• 64 GB Virtual Machine requires around 57 seconds on 10 GbE NIC.
• VMotion will check the remote system to make sure there is enough RAM and CPU before it begins the process.

Troubleshooting: –

• Migration ID is same on source and destination.
  • Go to VMkernel log (/var/log/vmkernel.log)
  • Grep the migration ID for all vMotion related timing and statistics.

That’s it from here. Stay connected.

About The Author

Dr. Pranay Jha

Dr. Pranay Jha is a Cloud and AI Consultant with 18+ years of experience in hybrid cloud, virtualization, and enterprise infrastructure transformation. He specializes in VMware technologies, multi-cloud strategy, and Generative AI solutions. He holds a PhD in Computer Applications with research focused on Cloud and AI, has published multiple research papers, and has been a VMware vExpert since 2016 and a VMUG Community Leader.

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