Chapter 11. Storage Concepts
11.1. Storage Pools
- virtio-blk = 2^63 bytes or 8 Exabytes(using raw files or disk)
- Ext4 = ~ 16 TB (using 4 KB block size)
- XFS = ~8 Exabytes
- qcow2 and host file systems keep their own metadata and scalability should be evaluated/tuned when trying very large image sizes. Using raw disks means fewer layers that could affect scalability or max size.
/var/lib/libvirt/images/directory, as the default storage pool. The default storage pool can be changed to another storage pool.
- Local storage pools - Local storage pools are directly attached to the host physical machine server. Local storage pools include: local directories, directly attached disks, physical partitions, and LVM volume groups. These storage volumes store guest virtual machine images or are attached to guest virtual machines as additional storage. As local storage pools are directly attached to the host physical machine server, they are useful for development, testing and small deployments that do not require migration or large numbers of guest virtual machines. 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 include storage devices shared over a network using standard protocols. Networked storage is required when migrating virtual machines between host physical machines with virt-manager, but is optional when migrating with virsh. Networked storage pools are managed by libvirt. Supported protocols for networked storage pools include:
- Fibre Channel-based LUNs
- SCSI RDMA protocols (SCSI RCP), the block export protocol used in InfiniBand and 10GbE iWARP adapters.