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 command
(for example by using a hard or soft link) it acts as that command.
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 substituted. 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 information 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
physical volumes.
- lvchange — Change attributes of a logical
volume.
- lvconvert — Convert a logical volume from
linear to mirror or snapshot.
- 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.
- --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
volume groups that are only partially available (one or more physical
volumes belonging to the volume group are missing from the system). Where
part of a logical volume is missing, /dev/ioerror 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 original 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
directory is mounted read-only when the script runs.
- --addtag tag
- Add the tag tag to a PV, VG or LV. Supply this
argument multiple 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 possess
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. Snapshots cannot be tagged.
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, anywhere 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. The default for a volume group is
normal which applies common-sense rules such as not placing
parallel 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 over-ridden on the command line of any command that
performs allocation. The contiguous policy requires that new
extents be placed adjacent to existing extents. The cling policy
places new extents on the same physical volume as existing extents in the
same stripe of the Logical Volume. If there are sufficient free 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.
- N.B. The policies described above are not implemented fully
yet. In particular, contiguous free space cannot be broken up to satisfy
allocation attempts.
ENVIRONMENT VARIABLES¶
- LVM_SYSTEM_DIR
- Directory containing lvm.conf and other LVM system files.
Defaults to "/etc/lvm".
- HOME
- Directory containing .lvm_history if the internal readline
shell is invoked.
- 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 contain the strings '_mlog', '_mimage',
'_rimage', '_tdata', '_tmeta'.
DIAGNOSTICS¶
All tools return a status code of zero on success or non-zero on failure.
FILES¶
/etc/lvm/lvm.conf
$HOME/.lvm_history
SEE ALSO¶
clvmd(8),
lvchange(8),
lvcreate(8),
lvdisplay(8),
lvextend(8),
lvmchange(8),
lvmdiskscan(8),
lvreduce(8),
lvremove(8),
lvrename(8),
lvresize(8),
lvs(8),
lvscan(8),
pvchange(8),
pvck(8),
pvcreate(8),
pvdisplay(8),
pvmove(8),
pvremove(8),
pvs(8),
pvscan(8),
vgcfgbackup(8),
vgchange(8),
vgck(8),
vgconvert(8),
vgcreate(8),
vgdisplay(8),
vgextend(8),
vgimport(8),
vgimportclone(8),
vgmerge(8),
vgmknodes(8),
vgreduce(8),
vgremove(8),
vgrename(8),
vgs(8),
vgscan(8),
vgsplit(8),
readline(3),
lvm.conf(5)