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.
- 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.