Sys::Virt::StorageVol(3)

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

  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
Copyright (C) 2006-2009 Red Hat Copyright (C) 2006-2009 Daniel P. Berrange

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.

SEE ALSO
Sys::Virt, Sys::Virt::Error, "http://libvirt.org"