Virsh vol-create-as

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Overview

Creates a storage volume from the given set of command-line arguments, unlike vol-create, which requires an XML file configuration.

virsh vol-create-as --pool <pool-name> --name <volume-name> --capacity <capacity> --format <fomat>

The --format is important, it could be "raw" or "qcow2". However, "qcow2" volumes are usually not required to be created manually, they can be create as part of the virtual machine provisioning with virt-install.

Before creating the volume, see:

Storage Volume Naming Convention

For command line examples, see Examples below.

After creation, the corresponding virtualization host filesystem file should be visible in the directory corresponding to the storage pool (ex. /main-storage-pool/docker-backend-storage.raw or /main-storage-pool/dp.qcow2).

Naming Convention

Storage Volume Naming Convention

Options

--pool

The pool name or pool UUID. The "--pool" label is optional if the pool name is specified as the first argument.

--name

The storage volume name. The "--name" label is optional if the storage volume name is specified as the second argument.

--capacity

The capacity, followed by one of the suffixes 'b', 'k', 'M', 'G', 'T'. The capacity is specified in bytes if there is no suffix. The "--capacity" label is optional if the capacity is specified as the third argument.

--print-xml

If specified, the volume is not created, only the XML of the volume object is printed out.

--allocation

The initial size to be allocated in the volume, as a scaled integer defaulting to bytes.

--format

Acceptable format types: "raw", "bochs", "qcow", "qcow2", "qed", "host_device", and "vmdk". These are, however, only meant for file based storage pools. By default the qcow version that is used is version 3.

--backing-vol

The source backing volume to be used if taking a snapshot of an existing volume.

--backing-vol-format

The format of the snapshot backing volume; raw, bochs, qcow, qcow2, qed, vmdk, host_device.

--prealloc-metadata

Preallocate metadata for qcow2 images that don't support full allocation. This option creates a sparse image file with metadata, resulting in higher performance compared to images with no preallocation and only slightly higher initial disk space usage.

Examples

Create a New Raw Block Storage Volume

virsh vol-create-as --pool main-storage-pool --name test-nfs.raw --capacity 1G --format raw