Installation guide

To allow safe migration of virtual machines between hosts with different sets of CPU features, q emu -

kvm does not expose all features from the host CPU to guest operating systems by default. Instead,

CPU features are exposed based on the chosen CPU model. If a virtual machine has a given CPU

feature enabled, it is not possible to migrate it to a host that does not support exposing that feature to

guests.

Note

For more information on guest CPU models, refer to the Red Hat Enterprise Linux 6 Virtualization

Host Configuration and Guest Installation Guide.

4.5. St orage

Storage for virtual machines is abstracted from the physical storage used by the virtual machine. It is

attached to the virtual machine using the para-virtualized or emulated block device drivers.

4 .5.1. St orage pools

A storage pool is a file, directory, or storage device managed by lib virt for the purpose of providing

storage to virtual machines. Storage pools are divided into storage volumes that store virtual

machine images or are attached to virtual machines as additional storage. Multiple guests can share

the same storage pool, allowing for better allocation of storage resources. Refer to the Red Hat

Enterprise Linux 6 Virtualization Administration Guide for more information.

Lo cal st o rag e p o o ls

Local storage pools are directly attached to the host server. They include local directories,

directly attached disks, physical partitions, and LVM volume groups on local devices. Local

storage pools are useful for development, testing and small deployments that do not require

migration or large numbers of virtual machines. Local storage pools may not be suitable for

many production environments as they do not support live migration.

Net wo rked ( sh ared ) st o rag e p o o ls

Networked storage pools include storage devices shared over a network using standard

protocols. Networked storage is required when migrating virtual machines between hosts

with virt - man ag er, but is optional when migrating with vi rsh. Networked storage pools

are managed by lib virt .

4 .5.2. St orage volumes

Storage pools are further divided into storage volumes. Storage volumes are an abstraction of

physical partitions, LVM logical volumes, file-based disk images and other storage types handled by

lib virt . Storage volumes are presented to virtual machines as local storage devices regardless of the

underlying hardware.

4 .5.3. Emulat ed st orage devices

The host emulates a range of storage devices that can be presented to virtual machines. Each type of

storage device is appropriate for specific use cases. Choice between different types of storage

devices allows for maximum flexibility and compatibility with guest operating systems.

virt io - scsi

Red Hat Ent erprise Linux 6 Virt ualizat io n G et t ing St art ed G uide