x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
LVM(8) System Manager's Manual LVM(8)
NAME
lvm - LVM2 tools
SYNOPSIS
lvm [command | file]
DESCRIPTION
lvm provides the command-line tools for LVM2. A separate manual page
describes each command in detail.
If lvm is invoked with no arguments it presents a readline prompt
(assuming it was compiled with readline support). LVM commands may be
entered interactively at this prompt with readline facilities including
history and command name and option completion. Refer to readline(3)
for details.
If lvm is invoked with argv[0] set to the name of a specific LVM com-
mand (for example by using a hard or soft link) it acts as that com-
mand.
On invocation, lvm requires that only the standard file descriptors
stdin, stdout and stderr are available. If others are found, they get
closed and messages are issued warning about the leak.
Where commands take VG or LV names as arguments, the full path name is
optional. An LV called "lvol0" in a VG called "vg0" can be specified
as "vg0/lvol0". Where a list of VGs is required but is left empty, a
list of all VGs will be substituted. Where a list of LVs is required
but a VG is given, a list of all the LVs in that VG will be substi-
tuted. So lvdisplay vg0 will display all the LVs in "vg0". Tags can
also be used - see --addtag below.
One advantage of using the built-in shell is that configuration infor-
mation gets cached internally between commands.
A file containing a simple script with one command per line can also be
given on the command line. The script can also be executed directly if
the first line is #! followed by the absolute path of lvm.
BUILT-IN COMMANDS
The following commands are built into lvm without links normally being
created in the filesystem for them.
dumpconfig -- Display the configuration information after
loading lvm.conf(5) and any other configuration files.
formats -- Display recognised metadata formats.
help -- Display the help text.
pvdata -- Not implemented in LVM2.
segtypes -- Display recognised Logical Volume segment types.
version -- Display version information.
COMMANDS
The following commands implement the core LVM functionality.
pvchange -- Change attributes of a Physical Volume.
pvck -- Check Physical Volume metadata.
pvcreate -- Initialize a disk or partition for use by LVM.
pvdisplay -- Display attributes of a Physical Volume.
pvmove -- Move Physical Extents.
pvremove -- Remove a Physical Volume.
pvresize -- Resize a disk or partition in use by LVM2.
pvs -- Report information about Physical Volumes.
pvscan -- Scan all disks for Physical Volumes.
vgcfgbackup -- Backup Volume Group descriptor area.
vgcfgrestore -- Restore Volume Group descriptor area.
vgchange -- Change attributes of a Volume Group.
vgck -- Check Volume Group metadata.
vgconvert -- Convert Volume Group metadata format.
vgcreate -- Create a Volume Group.
vgdisplay -- Display attributes of Volume Groups.
vgexport -- Make volume Groups unknown to the system.
vgextend -- Add Physical Volumes to a Volume Group.
vgimport -- Make exported Volume Groups known to the system.
vgimportclone -- Import and rename duplicated Volume Group (e.g. a
hardware snapshot).
vgmerge -- Merge two Volume Groups.
vgmknodes -- Recreate Volume Group directory and Logical Volume special
files
vgreduce -- Reduce a Volume Group by removing one or more
Physical Volumes.
vgremove -- Remove a Volume Group.
vgrename -- Rename a Volume Group.
vgs -- Report information about Volume Groups.
vgscan -- Scan all disks for Volume Groups and rebuild caches.
vgsplit -- Split a Volume Group into two, moving any logical
volumes from one Volume Group to another by moving entire Physi-
cal Volumes.
lvchange -- Change attributes of a Logical Volume.
lvconvert -- Convert a Logical Volume from linear to mirror or snap-
shot.
lvcreate -- Create a Logical Volume in an existing Volume Group.
lvdisplay -- Display attributes of a Logical Volume.
lvextend -- Extend the size of a Logical Volume.
lvmchange -- Change attributes of the Logical Volume Manager.
lvmdiskscan -- Scan for all devices visible to LVM2.
lvmdump -- Create lvm2 information dumps for diagnostic purposes.
lvreduce -- Reduce the size of a Logical Volume.
lvremove -- Remove a Logical Volume.
lvrename -- Rename a Logical Volume.
lvresize -- Resize a Logical Volume.
lvs -- Report information about Logical Volumes.
lvscan -- Scan (all disks) for Logical Volumes.
The following commands are not implemented in LVM2 but might be in the
future: lvmsadc, lvmsar, pvdata.
OPTIONS
The following options are available for many of the commands. They are
implemented generically and documented here rather than repeated on
individual manual pages.
-h, --help
Display the help text.
--version
Display version information.
-v, --verbose
Set verbose level. Repeat from 1 to 3 times to increase the
detail of messages sent to stdout and stderr. Overrides config
file setting.
-d, --debug
Set debug level. Repeat from 1 to 6 times to increase the detail
of messages sent to the log file and/or syslog (if configured).
Overrides config file setting.
-q, --quiet
Suppress output and log messages. Overrides -d and -v.
-t, --test
Run in test mode. Commands will not update metadata. This is
implemented by disabling all metadata writing but nevertheless
returning success to the calling function. This may lead to
unusual error messages in multi-stage operations if a tool
relies on reading back metadata it believes has changed but
hasn't.
--driverloaded {y|n}
Whether or not the device-mapper kernel driver is loaded. If
you set this to n, no attempt will be made to contact the
driver.
-A, --autobackup {y|n}
Whether or not to metadata should be backed up automatically
after a change. You are strongly advised not to disable this!
See vgcfgbackup(8).
-P, --partial
When set, the tools will do their best to provide access to Vol-
ume Groups that are only partially available (one or more Physi-
cal Volumes belonging to the Volume Group are missing from the
system). Where part of a logical volume is missing, /dev/ioer-
ror will be substituted, and you could use dmsetup(8) to set
this up to return I/O errors when accessed, or create it as a
large block device of nulls. Metadata may not be changed with
this option. To insert a replacement Physical Volume of the same
or large size use pvcreate -u to set the uuid to match the orig-
inal followed by vgcfgrestore(8).
-M, --metadatatype Type
Specifies which type of on-disk metadata to use, such as lvm1 or
lvm2, which can be abbreviated to 1 or 2 respectively. The
default (lvm2) can be changed by setting format in the global
section of the config file.
--ignorelockingfailure
This lets you proceed with read-only metadata operations such as
lvchange -ay and vgchange -ay even if the locking module fails.
One use for this is in a system init script if the lock direc-
tory is mounted read-only when the script runs.
--addtag Tag
Add the tag Tag to a PV, VG or LV. Supply this argument multi-
ple times to add more than one tag at once. A tag is a word
that can be used to group LVM2 objects of the same type
together. Tags can be given on the command line in place of PV,
VG or LV arguments. Tags should be prefixed with @ to avoid
ambiguity. Each tag is expanded by replacing it with all
objects possessing that tag which are of the type expected by
its position on the command line. PVs can only possess tags
while they are part of a Volume Group: PV tags are discarded if
the PV is removed from the VG. As an example, you could tag
some LVs as database and others as userdata and then activate
the database ones with lvchange -ay @database. Objects can pos-
sess multiple tags simultaneously. Only the new LVM2 metadata
format supports tagging: objects using the LVM1 metadata format
cannot be tagged because the on-disk format does not support it.
Characters allowed in tags are: A-Z a-z 0-9 _ + . - and as of
version 2.02.78 the following characters are also accepted: / =
! : # &
--deltag Tag
Delete the tag Tag from a PV, VG or LV, if it's present. Supply
this argument multiple times to remove more than one tag at
once.
--alloc AllocationPolicy
The allocation policy to use: contiguous, cling, normal, any-
where or inherit. When a command needs to allocate Physical
Extents from the Volume Group, the allocation policy controls
how they are chosen. Each Volume Group and Logical Volume has
an allocation policy defined. The default for a Volume Group is
normal which applies common-sense rules such as not placing par-
allel stripes on the same Physical Volume. The default for a
Logical Volume is inherit which applies the same policy as for
the Volume Group. These policies can be changed using
lvchange(8) and vgchange(8) or overridden on the command line of
any command that performs allocation. The contiguous policy
requires that new Physical Extents be placed adjacent to exist-
ing Physical Extents. The cling policy places new Physical
Extents on the same Physical Volume as existing Physical Extents
in the same stripe of the Logical Volume. If there are suffi-
cient free Physical Extents to satisfy an allocation request but
normal doesn't use them, anywhere will - even if that reduces
performance by placing two stripes on the same Physical Volume.
ENVIRONMENT VARIABLES
HOME Directory containing .lvm_history if the internal readline shell
is invoked.
LVM_SYSTEM_DIR
Directory containing lvm.conf(5) and other LVM system files.
Defaults to "/etc/lvm".
LVM_VG_NAME
The Volume Group name that is assumed for any reference to a
Logical Volume that doesn't specify a path. Not set by default.
VALID NAMES
The following characters are valid for VG and LV names: a-z A-Z 0-9 + _
. -
VG and LV names cannot begin with a hyphen. There are also various
reserved names that are used internally by lvm that can not be used as
LV or VG names. A VG cannot be called anything that exists in /dev/ at
the time of creation, nor can it be called '.' or '..'. A LV cannot be
called '.' '..' 'snapshot' or 'pvmove'. The LV name may also not con-
tain the strings '_mlog', '_mimage', '_rimage', '_tdata', '_tmeta'.
ALLOCATION
When an operation needs to allocate Physical Extents for one or more
Logical Volumes, the tools proceed as follows:
First of all, they generate the complete set of unallocated Physical
Extents in the Volume Group. If any ranges of Physical Extents are
supplied at the end of the command line, only unallocated Physical
Extents within those ranges on the specified Physical Volumes are con-
sidered.
Then they try each allocation policy in turn, starting with the
strictest policy (contiguous) and ending with the allocation policy
specified using --alloc or set as the default for the particular Logi-
cal Volume or Volume Group concerned. For each policy, working from
the lowest-numbered Logical Extent of the empty Logical Volume space
that needs to be filled, they allocate as much space as possible
according to the restrictions imposed by the policy. If more space is
needed, they move on to the next policy.
The restrictions are as follows:
Contiguous requires that the physical location of any Logical Extent
that is not the first Logical Extent of a Logical Volume is adjacent to
the physical location of the Logical Extent immediately preceding it.
Cling requires that the Physical Volume used for any Logical Extent to
be added to an existing Logical Volume is already in use by at least
one Logical Extent earlier in that Logical Volume. If the configura-
tion parameter allocation/cling_tag_list is defined, then two Physical
Volumes are considered to match if any of the listed tags is present on
both Physical Volumes. This allows groups of Physical Volumes with
similar properties (such as their physical location) to be tagged and
treated as equivalent for allocation purposes.
When a Logical Volume is striped or mirrored, the above restrictions
are applied independently to each stripe or mirror image (leg) that
needs space.
Normal will not choose a Physical Extent that shares the same Physical
Volume as a Logical Extent already allocated to a parallel Logical Vol-
ume (i.e. a different stripe or mirror image/leg) at the same offset
within that parallel Logical Volume.
When allocating a mirror log at the same time as Logical Volumes to
hold the mirror data, Normal will first try to select different Physi-
cal Volumes for the log and the data. If that's not possible and the
allocation/mirror_logs_require_separate_pvs configuration parameter is
set to 0, it will then allow the log to share Physical Volume(s) with
part of the data.
When allocating thin pool metadata, similar considerations to those of
a mirror log in the last paragraph apply based on the value of the
allocation/thin_pool_metadata_require_separate_pvs configuration param-
eter.
If you rely upon any layout behaviour beyond that documented here, be
aware that it might change in future versions of the code.
For example, if you supply on the command line two empty Physical Vol-
umes that have an identical number of free Physical Extents available
for allocation, the current code considers using each of them in the
order they are listed, but there is no guarantee that future releases
will maintain that property. If it is important to obtain a specific
layout for a particular Logical Volume, then you should build it up
through a sequence of lvcreate(8) and lvconvert(8) steps such that the
restrictions described above applied to each step leave the tools no
discretion over the layout.
To view the way the allocation process currently works in any specific
case, read the debug logging output, for example by adding -vvvv to a
command.
DIAGNOSTICS
All tools return a status code of zero on success or non-zero on fail-
ure.
FILES
/etc/lvm/lvm.conf
$HOME/.lvm_history
SEE ALSO
clvmd(8), lvchange(8), lvcreate(8), lvdisplay(8), lvextend(8), lvm-
change(8), lvmdiskscan(8), lvreduce(8), lvremove(8), lvrename(8), lvre-
size(8), lvs(8), lvscan(8), pvchange(8), pvck(8), pvcreate(8), pvdis-
play(8), pvmove(8), pvremove(8), pvs(8), pvscan(8), vgcfgbackup(8),
vgchange(8), vgck(8), vgconvert(8), vgcreate(8), vgdisplay(8), vgex-
tend(8), vgimport(8), vgimportclone(8), vgmerge(8), vgmknodes(8), vgre-
duce(8), vgremove(8), vgrename(8), vgs(8), vgscan(8), vgsplit(8), read-
line(3), lvm.conf(5)
Sistina Software UK LVM TOOLS 2.02.98(2) (2012-10-15) LVM(8)
Want to link to this manual page? Use this URL:
<http://star2.abcm.com/cgi-bin/bsdi-man?query=lvm&sektion=8&manpath=>