Installation guide

An offline migration suspends the guest virtual machine, and then moves an image of the
virtual machine's memory to the destination host. The virtual machine is then resumed on
the destination host and the memory used by the virtual machine on the source host is
freed.
Live mig rat io n
Live migration is the process of migrating an active virtual machine from one physical host
to another.
2.2.1. Benefit s of migrat ing virt ual machines
Migration is useful for:
Lo ad b alan cin g
When a host machine is overloaded, one or many of its virtual machines could be migrated
to other hosts using live migration.
Up g rad in g o r makin g ch an g es t o t h e h o st
When the need arises to upgrade, add, or remove hardware devices on one host, virtual
machines can be safely relocated to other hosts. This means that guests do not experience
any downtime due to changes that are made to any of the hosts.
En erg y savin g
Virtual machines can be redistributed to other hosts and the unloaded host systems can be
powered off to save energy and cut costs in low usage periods.
G eo g rap h ic mig rat io n
Virtual machines can be moved to another physical location for lower latency or for other
special circumstances.
It is important to understand that the migration process moves the virtual machine's memory, and
from Red Hat Enterprise Linux 6.3, the disk volume associated with the virtual machine is also
migrated. This process is done using live block migration.
Shared, networked storage can be used to store guest images to be migrated. When migrating virtual
machines, it is recommended to use lib virt -managed storage pools for shared storage.
Note
For more information on migration, refer to the Red Hat Enterprise Linux 6 Virtualization
Administration Guide.
2.3. Virt ualized t o virt ualized migrat ion (V2V)
Red Hat Enterprise Linux 6 provides tools for converting virtual machines from other types of
hypervisors to KVM. The vi rt-v2v tool converts and imports virtual machines from Xen, other
versions of KVM, VMware ESX, and Hyper-V.
From Red Hat Enterprise Linux 6.5, the vi rt-v2v tool converts and imports virtual machines with
virtual disk image formats including VHDX, VMDK, OVF, raw, and qcow2.
Red Hat Ent erprise Linux 6 Virt ualizat io n G et t ing St art ed G uide
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