Live migration

You can use the unlimited number of physical servers within interface of a single VMmanager, thus building a cluster of servers. Virtual machine images can be moved between cluster nodes. This process is called migration.

Why is migration needed?

One of the customers upgraded its tariff plan but the current node doesn’t have any additional resources available.
Administrator has to put the server on maintenance e.g. to repair coolers or upgrade RAM.
Provider wants to redistribute virtual machines between physical servers to use available infrastructure more practically.
Other scenarios.

Types of migration in VMmanager

Migration uses different mechanisms, depending on VMmanager version. In KVM migration is done with libvirt, while OVZ uses vzmigrate.

Live migration. Virtual machine is available and continues to operate. Live migration is a good tool for smaller virtual machines that are not used very actively. Otherwise, there is a risk that some data can be lost during continuous rewriting process.
Standard migration. Virtual machine is suspended before migration and is not available during the process. Standard migration is normally used to transfer virtual machines with smaller disks.
Migration of a suspended virtual machine. If a virtual machine is suspended, migration can be performed by copying data (copying a disk image of the machine). It is the most secure way to migrate a large virtual machine.

Main features

Why is migration needed?

Types of migration in VMmanager