NAME

Sys::Virt::StorageVol - Represent & manage a libvirt storage volume

DESCRIPTION

The "Sys::Virt::StorageVol" module represents a storage volume managed by libvirt. A storage volume is always associated with a containing storage pool ("Sys::Virt::StoragePool").

METHODS

my $name = $vol->get_name(): Returns a string with a locally unique name of the storage vol
my $name = $vol->get_key(): Returns a string with a globally unique key for the storage vol
my $name = $vol->get_path(): Returns a string with a locally unique file path of the storage vol
my $xml = $vol->get_xml_description(): Returns an XML document containing a complete description of the storage vol's configuration
$vol->delete($flags): Immediately delete the storage volume freeing its storage resources. The "flags" parameter indicates any special action to be taken when deleting the volume.
$vol->resize($newcapacity, $flags=0): Adjust the size of the storage volume. The $newcapacity value semantics depend on the $flags parameter. If $flags specifies "RESIZE_DELTA" then the $newcapacity is relative to the current size. If $flags specifies "RESIZE_SHRINK" then the $newcapacity value is the amount of space to remove
$vol->wipe($flags = 0): Clear the data in the storage volume to avoid future information leak. The "flags" parameter is currently unused and defaults to zero.
$vol->wipe_pattern($algorithm, $flags = 0): Clear the data in the storage volume to avoid future information leak. The $algorithm parameter specifies the data pattern used to erase data, and should be one of the WIPE ALGORITHM CONSTANTS listed later. The "flags" parameter is currently unused and defaults to zero.
my $info = $vol->get_info($flags = 0): Retrieve live information about the storage volume. The returned $info hash reference contains three keys. "type" indicates whether the volume is a file or block device. "capacity" provides the maximum logical size of the volume. "allocation" provides the current physical usage of the volume. The allocation may be less than the capacity for sparse, or grow-on-demand volumes. The allocation may also be larger than the capacity, if there is a metadata overhead for the volume format. $flags may take one of the values

Sys::Virt::StorageVol::USE_ALLOCATION: Return the current allocation in allocation
Sys::Virt::StorageVol::GET_PHYSICAL: Return the physical size in allocation

$vol->download($st, $offset, $length, $flags=0);: Download data from $vol using the stream $st. If $offset and $length are non-zero, then restrict data to the specified volume byte range. The $flags accept the following values:

Sys::Virt::StorageVol::VOL_DOWNLOAD_SPARSE_STREAM: If this flag is is set in @flags effective transmission of holes is enabled. This assumes using the stream $st with combination of "sparse_recv_all" or "recv($flags = VIR_STREAM_RECV_STOP_AT_HOLE)" for honouring holes sent by server.

$vol->upload($st, $offset, $length, $flags=0);: Upload data to $vol using the stream $st. If $offset and $length are non-zero, then restrict data to the specified volume byte range. The $flags accept the following values:

Sys::Virt::StorageVol::VOL_UPLOAD_SPARSE_STREAM: If this is set in $flags effective transmission of holes is enabled. This assumes using the stream $st with combination of "sparse_send_all" or "send_hole" to preserve source file sparseness.

CONSTANTS

The following sets of constants are useful when dealing with storage volumes

VOLUME TYPES

The following constants are useful for interpreting the "type" field in the hash returned by the "get_info" method

Sys::Virt::StorageVol::TYPE_FILE: The volume is a plain file
Sys::Virt::StorageVol::TYPE_BLOCK: The volume is a block device
Sys::Virt::StorageVol::TYPE_DIR: The volume is a directory
Sys::Virt::StorageVol::TYPE_NETWORK: The volume is a network source
Sys::Virt::StorageVol::TYPE_NETDIR: The volume is a network directory
Sys::Virt::StorageVol::TYPE_PLOOP: The volume is a ploop directory

CREATE MODES

The following constants are useful for the "flags" parameter of the "create" method

Sys::Virt::StorageVol::CREATE_PREALLOC_METADATA: Preallocate header metadata when creating the volume.
Sys::Virt::StorageVol::CREATE_REFLINK: Perform lightweight reference copy
Sys::Virt::StorageVol::CREATE_VALIDATE: Validate the XML document against schema

DELETE MODES

The following constants are useful for the "flags" parameter of the "delete" method

Sys::Virt::StorageVol::DELETE_NORMAL: Do a plain delete without any attempt to scrub data.
Sys::Virt::StorageVol::DELETE_ZEROED: Zero out current allocated blocks when deleting the volume
Sys::Virt::StorageVol::DELETE_WITH_SNAPSHOTS: Delete snapshots associated with the volume

WIPE ALGORITHM CONSTANTS

The following constants specify the algorithm for erasing data

Sys::Virt::StorageVol::WIPE_ALG_BSI: 9-pass method recommended by the German Center of Security in Information Technologies
Sys::Virt::StorageVol::WIPE_ALG_DOD: 4-pass Dod 5220.22-M section, 8-306 procedure
Sys::Virt::StorageVol::WIPE_ALG_GUTMANN: The canonical 35-pass sequence
Sys::Virt::StorageVol::WIPE_ALG_NNSA: 4-pass NNSA Policy Letter NAP-14.1-C (XVI-8)
Sys::Virt::StorageVol::WIPE_ALG_PFITZNER7: 7-pass random
Sys::Virt::StorageVol::WIPE_ALG_PFITZNER33: 33-pass random
Sys::Virt::StorageVol::WIPE_ALG_RANDOM: 1-pass random
Sys::Virt::StorageVol::WIPE_ALG_SCHNEIER: 7-pass method described by Bruce Schneier in "Applied Cryptography" (1996)
Sys::Virt::StorageVol::WIPE_ALG_ZERO: 1-pass, all zeroes
Sys::Virt::StorageVol::WIPE_ALG_TRIM: 1-pass, trim all data on the volume by using TRIM or DISCARD

VOLUME RESIZE CONSTANTS

The following constants control how storage volumes can be resized

Sys::Virt::StorageVol::RESIZE_ALLOCATE: Fully allocate the extra space required during resize
Sys::Virt::StorageVol::RESIZE_DELTA: Treat the new capacity as a delta to the current capacity
Sys::Virt::StorageVol::RESIZE_SHRINK: Treat the new capacity as an amount to remove from the capacity

AUTHORS

Daniel P. Berrange <berrange@redhat.com>

COPYRIGHT

LICENSE

This program is free software; you can redistribute it and/or modify it under the terms of either the GNU General Public License as published by the Free Software Foundation (either version 2 of the License, or at your option any later version), or, the Artistic License, as specified in the Perl README file.