Migrating VMs

In simple terms, migration enables you to move your VM from one physical machine to another physical machine, with a very minimal downtime or no downtime. We can also move VM storage, which is a resource-hog type of operation that needs to be carefully planned and—if possible —executed after hours so that it doesn't affect other VMs' performance as much as it could.

There are various different types of migration, as follows:

• Offline (cold)
• Online (live)
• Suspended migration

There are also various different types of online migrations, depending on what you're moving, as follows:

• The compute part of the VM (moving the VM from one KVM host to another KVM host)
• The storage part of the VM (moving VM files from one storage pool to another storage pool)
• Both (moving the VM from host to host and storage pool to storage pool at the same time)

There are some differences in terms of which migration scenarios...