Installation guide

Chapter 1. Introduction
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in the PCI configuration space as multiple functions, each device has its own configuration space
complete with Base Address Registers (BARs).
SR-IOV uses two new PCI functions:
• Virtualization-PF
• Virtualization VF
For more information on SR-IOV, refer to Chapter 13, SR-IOV.
NPIV
N_Port ID Virtualization (NPIV) is a function available with some Fibre Channel devices. NPIV shares
a single physical N_Port as multiple N_Port IDs. NPIV provides similar functionality for Host Bus
Adaptors (HBAs) that SR-IOV provides for network interfaces. With NPIV, virtualized guests can be
provided with a virtual Fibre Channel initiator to Storage Area Networks (SANs).
NPIV can provide high density virtualized environments with enterprise-level storage solutions.
For more information on NPIV, refer to Chapter 29, N_Port ID Virtualization (NPIV).
1.5. Storage
Storage for virtualized guests is abstracted from the physical storage used by the guest. Storage is
attached to virtualized guests using the para-virtualized (Section 1.4.2, “Para-virtualized drivers”) or
emulated block device drivers (Emulated storage drivers).
Storage pools
A storage pool is a file, directory, or storage device managed by libvirt for the purpose of providing
storage to virtualized guests. Storage pools are divided into storage volumes that store virtualized
guest images or are attached to virtualized guests as additional storage.
Storage pools can be divided up into volumes or allocated directly to a guest. Volumes of a storage
pool can be allocated to virtualized guests. There are two categories of storage pool available:
Local storage pools
Local storage pools are directly attached to the host server. Local storage pools include local
directories, directly attached disks, 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 virtualized guests. Local storage pools are not suitable for many
production environments as local storage pools do not support live migration.
Networked (shared) storage pools
Networked storage pools covers storage devices shared over a network using standard protocols.
Networked storage required for migrating guest virtualized guests between hosts. Networked storage
pools are managed by libvirt.
Storage volumes
Storage pools are 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 libvirt.