NAME¶
lvcreate - create a logical volume in an existing volume group
SYNOPSIS¶
lvcreate [
--addtag Tag] [
--alloc
AllocationPolicy] [
-a|
--activate
[
a|
e|
l]{
y|
n}]
[
-k|
--setactivationskip {
y|
n}]
[
-K|
--ignoreactivationskip] [
-A|
--autobackup
{
y|
n}] [
--commandprofile ProfileName]
[
-C|
--contiguous {
y|
n}] [
-d|
--debug]
[
-h|
-?|
--help] [
--noudevsync]
[
--ignoremonitoring] [
--metadataprofile ProfileName]
[
--monitor {
y|
n}] [
--[raid]maxrecoveryrate
Rate] [
--[raid]minrecoveryrate Rate]
[
-i|
--stripes Stripes [
-I|
--stripesize
StripeSize]] {[
-l|
--extents
LogicalExtentsNumber[
%{
VG|
PVS|
FREE}] |
-L|
--size LogicalVolumeSize[
bBsSkKmMgGtTpPeE]] |
-V|
--virtualsize VirtualSize[
bBsSkKmMgGtTpPeE]}
[
-M|
--persistent {
y|
n}] [
--minor
minor] [
-m|
--mirrors Mirrors [
--nosync]
[
--mirrorlog {
disk|
core|
mirrored} |
--corelog] [
-R|
--regionsize MirrorLogRegionSize]]
[
-n|
--name LogicalVolume{
Name|
Path}]
[
-p|
--permission {
r|
rw}]
[
-r|
--readahead
{
ReadAheadSectors|
auto|
none}] [
-t|
--test]
[
-T|
--thin [
--cachemode
{
writeback|
writethrough} [
-c|
--chunksize
ChunkSize[
bBsSkKmMgG]] [
--discards
{
ignore|
nopassdown|
passdown}] [
--poolmetadatasize
MetadataVolumeSize[
bBsSkKmMgG]] [
--poolmetadataspare
{
y|
n}]] [
--thinpool
ThinPoolLogicalVolume{
Name|
Path}
[
-s|
--snapshot [
VolumeGroup{
Name|
Path}/]
ExternalOriginLogicalVolumeName]] [
--type SegmentType]
[
-v|
--verbose] [
-W|
--wipesignatures]
[
-Z|
--zero {
y|
n}]
VolumeGroup{
Name|
Path}[/
ThinPoolLogicalVolumeName]
[
PhysicalVolumePath[
:PE[
-PE]]...]
lvcreate [
-l|
--extents
LogicalExtentsNumber[
%{
ORIGIN|
VG|
PVS|
FREE}]
|
-L|
--size LogicalVolumeSize[
bBsSkKmMgGtTpPeE]]
[
-c|
--chunksize ChunkSize[
bBsSkK]]
[
--commandprofile Profilename] [
--noudevsync]
[
--ignoremonitoring] [
--metadataProfile ProfileName]
[
--monitor {
y|
n}] [
-n|
--name
SnapshotLogicalVolume{
Name|
Path}]
-s|
--snapshot
{[
VolumeGroup{
Name|
Path}/]
OriginalLogicalVolumeName
-V|
--virtualsize VirtualSize[
bBsSkKmMgGtTpPeE]}
DESCRIPTION¶
lvcreate creates a new logical volume in a volume group (see
vgcreate(8),
vgchange(8)) by allocating logical extents from the free physical
extent pool of that volume group. If there are not enough free physical
extents then the volume group can be extended (see
vgextend(8)) with
other physical volumes or by reducing existing logical volumes of this volume
group in size (see
lvreduce(8)). If you specify one or more
PhysicalVolumes, allocation of physical extents will be restricted to these
volumes.
The second form supports the creation of snapshot logical volumes which keep the
contents of the original logical volume for backup purposes.
OPTIONS¶
See
lvm(8) for common options.
- -a, --activate
{y|ay|n|ey|en|ly|ln}
- Controls the availability of the Logical Volumes for immediate use after
the command finishes running. By default, new Logical Volumes are
activated ( -ay). If it is possible technically,
-an will leave the new Logical Volume inactive. But for
example, snapshots can only be created in the active state so
-an cannot be used with --snapshot. Normally the
--zero n argument has to be supplied too because zeroing
(the default behaviour) also requires activation. If autoactivation option
is used ( -aay), the logical volume is activated only if it
matches an item in the activation/auto_activation_volume_list set
in lvm.conf(5). For autoactivated logical volumes, --zero
n and --wipesignatures n is always assumed and it
can't be overridden. If the clustered locking is enabled,
-aey will activate exclusively on one node and
-a{a|l}y
will activate only on the local node.
- -k, --setactivationskip
{y|n}
- Controls whether Logical Volumes are persistently flagged to be skipped
during activation. By default, thin snapshot volumes are flagged for
activation skip. To activate such volumes, an extra
-K/--ignoreactivationskip option must be used. The flag is not
applied during deactivation. Use lvchange -k/--setactivationskip
{y|n} command to attach or detach the flag for existing volumes. To
see whether the flag is attached, use lvs command where the state
of the flag is reported within lv_attr bits.
- -K, --ignoreactivationskip
- Ignore the flag to skip Logical Volumes during activation.
- --cachemode
{writeback|writethrough}
- Specifying a cache mode determines when the writes to a cache LV are
considered complete. When writeback is specified, a write is
considered complete as soon as it is stored in the cache pool LV. If
writethough is specified, a write is considered complete only when
it has been stored in the cache pool LV and on the origin LV. While
writethrough may be slower for writes, it is more resilient if
something should happen to a device associated with the cache pool LV.
- -c, --chunksize
ChunkSize[bBsSkKmMgG]
- Gives the size of chunk for snapshot, cache pool and thin pool logical
volumes. Default unit is in kilobytes.
For snapshots the value must be power of 2 between 4KiB and 512KiB and the
default value is 4.
For cache pool LVs the value must be between 32KiB and 1GiB. The default is
64KiB. Values must be a multiple of 32KiB.
For thin pools the value must be between 64KiB and 1GiB and the default
value starts with 64 and scales up to fit the pool metadata size within
128MiB, if the pool metadata size is not specified. Thin pool target
version <1.4 requires the value to be a power of 2. The newer target
version relaxes limitation to be a multiple of 64KiB. For target version
<1.5 discard is not supported for non power of 2 values.
- -C, --contiguous
{y|n}
- Sets or resets the contiguous allocation policy for logical volumes.
Default is no contiguous allocation based on a next free principle.
- --discards
{ignore|nopassdown|passdown}
- Sets discards behavior for thin pool. Default is passdown.
- -i, --stripes Stripes
- Gives the number of stripes. This is equal to the number of physical
volumes to scatter the logical volume. When creating a RAID 4/5/6 logical
volume, the extra devices which are necessary for parity are internally
accounted for. Specifying -i3 would use 3 devices for
striped logical volumes, 4 devices for RAID 4/5, and 5 devices for RAID 6.
Alternatively, RAID 4/5/6 will stripe across all PVs in the volume group
or all of the PVs specified if the -i argument is omitted.
- -I, --stripesize StripeSize
- Gives the number of kilobytes for the granularity of the stripes.
StripeSize must be 2^n (n = 2 to 9) for metadata in LVM1 format. For
metadata in LVM2 format, the stripe size may be a larger power of 2 but
must not exceed the physical extent size.
- --ignoremonitoring
- Make no attempt to interact with dmeventd unless --monitor is
specified.
- -l, --extents
LogicalExtentsNumber[%{VG|PVS|FREE|ORIGIN}]
- Gives the number of logical extents to allocate for the new logical
volume. The total number of physical extents allocated will be greater
than this, for example, if the volume is mirrored. The number can also be
expressed as a percentage of the total space in the Volume Group with the
suffix %VG, as a percentage of the remaining free space in the
Volume Group with the suffix %FREE, as a percentage of the
remaining free space for the specified PhysicalVolume(s) with the suffix
%PVS, or (for a snapshot) as a percentage of the total space in the
Origin Logical Volume with the suffix %ORIGIN (i.e.
100%ORIGIN provides space for the whole origin). When expressed as
a percentage, the number is treated as an approximate upper limit for the
total number of physical extents to be allocated (including extents used
by any mirrors, for example).
- -L, --size
LogicalVolumeSize[bBsSkKmMgGtTpPeE]
- Gives the size to allocate for the new logical volume. A size suffix of
B for bytes, S for sectors as 512 bytes, K for
kilobytes, M for megabytes, G for gigabytes, T for
terabytes, P for petabytes or E for exabytes is optional.
Default unit is megabytes.
- -m, --mirrors Mirrors
- Creates a mirrored logical volume with Mirrors copies. For example,
specifying -m1 would result in a mirror with two-sides; that
is, a linear volume plus one copy.
Specifying the optional argument --nosync will cause the creation of
the mirror to skip the initial resynchronization. Any data written
afterwards will be mirrored, but the original contents will not be copied.
This is useful for skipping a potentially long and resource intensive
initial sync of an empty device.
There are two implementations of mirroring which can be used and correspond
to the "raid1" and "mirror" segment types. The default
is "raid1". See the --type option for more information if
you would like to use the legacy "mirror" segment type. The
--mirrorlog and --corelog options apply to the
"mirror" segment type only.
The optional argument --mirrorlog specifies the type of log to be
used for logical volumes utilizing the legacy "mirror" segment
type. The default is disk, which is persistent and requires a small
amount of storage space, usually on a separate device from the data being
mirrored. Using core means the mirror is regenerated by copying the
data from the first device each time the logical volume is activated, like
after every reboot. Using mirrored will create a persistent log
that is itself mirrored.
When the legacy "mirror" segment type is used, the optional
argument --corelog is equivalent to --mirrorlog
core.
- --metadataprofile ProfileName
- Uses and attaches the ProfileName configuration profile to the logical
volume metadata. Whenever the logical volume is processed next time, the
profile is automatically applied. If the volume group has another profile
attached, the logical volume profile is preferred. See lvm.conf(5)
for more information about metadata profiles.
- -M, --persistent
{y|n}
- Set to y to make the minor number specified persistent.
- --minor minor
- Sets the minor number.
- --monitor
{y|n}
- Starts or avoids monitoring a mirrored, snapshot or thin pool logical
volume with dmeventd, if it is installed. If a device used by a monitored
mirror reports an I/O error, the failure is handled according to
activation/mirror_image_fault_policy and
activation/mirror_log_fault_policy set in lvm.conf(5).
- -n, --name
LogicalVolume{Name|Path}
- Sets the name for the new logical volume.
Without this option a default name of "lvol#" will be generated
where # is the LVM internal number of the logical volume.
- --[raid]maxrecoveryrate
Rate[bBsSkKmMgG]
- Sets the maximum recovery rate for a RAID logical volume. Rate is
specified as an amount per second for each device in the array. If no
suffix is given, then KiB/sec/device is assumed. Setting the recovery rate
to 0 means it will be unbounded.
- --[raid]minrecoveryrate
Rate[bBsSkKmMgG]
- Sets the minimum recovery rate for a RAID logical volume. Rate is
specified as an amount per second for each device in the array. If no
suffix is given, then KiB/sec/device is assumed. Setting the recovery rate
to 0 means it will be unbounded.
- --noudevsync
- Disables udev synchronisation. The process will not wait for notification
from udev. It will continue irrespective of any possible udev processing
in the background. You should only use this if udev is not running or has
rules that ignore the devices LVM2 creates.
- -p, --permission
{r|rw}
- Sets access permissions to read only (r) or read and write
(rw).
Default is read and write.
- --poolmetadatasize
MetadataVolumeSize[bBsSkKmMgG]
- Sets the size of thin pool's metadata logical volume. Supported values are
in range between 2MiB and 16GiB. Default value is (Pool_LV_size /
Pool_LV_chunk_size * 64b). Default unit is megabytes.
- --poolmetadataspare
{y|n}
- Controls creation and maintanence of pool metadata spare logical volume
that will be used for automated pool recovery. Only one such volume is
maintained within a volume group with the size of the biggest pool
metadata volume. Default is yes.
- -r, --readahead
{ReadAheadSectors|auto|none}
- Sets read ahead sector count of this logical volume. For volume groups
with metadata in lvm1 format, this must be a value between 2 and 120. The
default value is auto which allows the kernel to choose a suitable
value automatically. None is equivalent to specifying zero.
- -R, --regionsize MirrorLogRegionSize
- A mirror is divided into regions of this size (in MiB), and the mirror log
uses this granularity to track which regions are in sync.
- -s, --snapshot
OriginalLogicalVolume{Name|Path}
- Creates a snapshot logical volume (or snapshot) for an existing, so called
original logical volume (or origin). Snapshots provide a 'frozen image' of
the contents of the origin while the origin can still be updated. They
enable consistent backups and online recovery of removed/overwritten
data/files. Thin snapshot is created when the origin is a thin volume and
the size IS NOT specified. Thin snapshot shares same blocks within the
thin pool volume. The non thin volume snapshot with the specified size
does not need the same amount of storage the origin has. In a typical
scenario, 15-20% might be enough. In case the snapshot runs out of
storage, use lvextend(8) to grow it. Shrinking a snapshot is
supported by lvreduce(8) as well. Run lvs(8) on the snapshot
in order to check how much data is allocated to it. Note: a small amount
of the space you allocate to the snapshot is used to track the locations
of the chunks of data, so you should allocate slightly more space than you
actually need and monitor ( --monitor) the rate at which the
snapshot data is growing so you can avoid running out of space. If
--thinpool is specified, thin volume is created that will use given
original logical volume as an external origin that serves unprovisioned
blocks. Only read-only volumes can be used as external origins. To make
the volume external origin, lvm expects the volume to be inactive.
External origin volume can be used/shared for many thin volumes even from
different thin pools. See lvconvert(8) for online conversion to
thin volumes with external origin.
- -T, --thin,
--thinpool
ThinPoolLogicalVolume{Name|Path}
- Creates thin pool or thin logical volume or both. Specifying the optional
argument --size will cause the creation of the thin pool logical
volume. Specifying the optional argument --virtualsize will cause
the creation of the thin logical volume from given thin pool volume.
Specifying both arguments will cause the creation of both thin pool and
thin volume using this pool. See lvmthin(7) for more info about
thin provisioning support. Requires device mapper kernel driver for thin
provisioning from kernel 3.2 or newer.
- --type SegmentType
- Create a logical volume that uses the specified segment type (e.g.
mirror(-m), raid5,
snapshot(-s),
thin(-T), thin-pool, ...). Many
segment types have a commandline switch alias that will enable their use (
-s is an alias for --type snapshot). However, this
argument must be used when no existing commandline switch alias is
available for the desired type, as is the case with cache,
error, raid1, raid4, raid5, raid6,
raid10 or zero. See lvmcache(7) for more info about
caching support. Note that the cache segment type requires a dm-cache
kernel module version 1.3.0 or greater.
- -V, --virtualsize
VirtualSize[
bBsSkKmMgGtTpPeE]
- Creates a sparse device of the given size (in MiB by default) using a
snapshot or thinly provisioned device when thin pool is specified.
Anything written to the device will be returned when reading from it.
Reading from other areas of the device will return blocks of zeros.
Virtual snapshot is implemented by creating a hidden virtual device of the
requested size using the zero target. A suffix of _vorigin is used for
this device. Note: using sparse snapshots is not efficient for larger
device sizes (GiB), thin provisioning should be used for this case.
- -W, --wipesignatures
{y|n}
- Controls wiping of detected signatures on newly created Logical Volume. If
this option is not specified, then by default signature wiping is done
each time the zeroing ( -Z/--zero) is done. This default
behaviour can be controlled by
allocation/wipe_signatures_when_zeroing_new_lvs setting found in
lvm.conf(5).
If blkid wiping is used ( allocation/use_blkid_wiping setting in
lvm.conf(5)) and LVM2 is compiled with blkid wiping support, then
blkid(8) library is used to detect the signatures (use blkid
-k command to list the signatures that are recognized). Otherwise,
native LVM2 code is used to detect signatures (MD RAID, swap and LUKS
signatures are detected only in this case).
Logical Volume is not wiped if the read only flag is set.
- -Z, --zero
{y|n}
- Controls zeroing of the first 4KiB of data in the new logical volume.
Default is yes.
Volume will not be zeroed if the read only flag is set.
Snapshot volumes are zeroed always.
Warning: trying to mount an unzeroed logical volume can cause the system to
hang.
Examples¶
Creates a striped logical volume with 3 stripes, a stripe size of 8KiB and a
size of 100MiB in the volume group named vg00. The logical volume name will be
chosen by lvcreate:
lvcreate -i 3 -I 8 -L 100M vg00
Creates a mirror logical volume with 2 sides with a useable size of 500 MiB.
This operation would require 3 devices (or option
--alloc anywhere ) - two for the mirror devices and one
for the disk log:
lvcreate -m1 -L 500M vg00
Creates a mirror logical volume with 2 sides with a useable size of 500 MiB.
This operation would require 2 devices - the log is "in-memory":
lvcreate -m1 --mirrorlog core -L 500M vg00
Creates a snapshot logical volume named "vg00/snap" which has access
to the contents of the original logical volume named "vg00/lvol1" at
snapshot logical volume creation time. If the original logical volume contains
a file system, you can mount the snapshot logical volume on an arbitrary
directory in order to access the contents of the filesystem to run a backup
while the original filesystem continues to get updated:
lvcreate --size 100m --snapshot --name snap /dev/vg00/lvol1
Creates a snapshot logical volume named "vg00/snap" with size for
overwriting 20% of the original logical volume named "vg00/lvol1".:
lvcreate -s -l 20%ORIGIN --name snap vg00/lvol1
Creates a sparse device named /dev/vg1/sparse of size 1TiB with space for just
under 100MiB of actual data on it:
lvcreate --virtualsize 1T --size 100M --snapshot --name sparse vg1
Creates a linear logical volume "vg00/lvol1" using physical extents
/dev/sda:0-7 and /dev/sdb:0-7 for allocation of extents:
lvcreate -L 64M -n lvol1 vg00 /dev/sda:0-7 /dev/sdb:0-7
Creates a 5GiB RAID5 logical volume "vg00/my_lv", with 3 stripes (plus
a parity drive for a total of 4 devices) and a stripesize of 64KiB:
lvcreate --type raid5 -L 5G -i 3 -I 64 -n my_lv vg00
Creates a RAID5 logical volume "vg00/my_lv", using all of the free
space in the VG and spanning all the PVs in the VG:
lvcreate --type raid5 -l 100%FREE -n my_lv vg00
Creates a 5GiB RAID10 logical volume "vg00/my_lv", with 2 stripes on 2
2-way mirrors. Note that the
-i and
-m arguments behave
differently. The
-i specifies the number of stripes. The
-m
specifies the number of
additional copies:
lvcreate --type raid10 -L 5G -i 2 -m 1 -n my_lv vg00
Creates 100MiB pool logical volume for thin provisioning build with 2 stripes
64KiB and chunk size 256KiB together with 1TiB thin provisioned logical volume
"vg00/thin_lv":
lvcreate -i 2 -I 64 -c 256 -L100M -T vg00/pool -V 1T --name thin_lv
Creates a thin snapshot volume "thinsnap" of thin volume
"thinvol" that will share the same blocks within the thin pool.
Note: the size MUST NOT be specified, otherwise the non-thin snapshot is
created instead:
lvcreate -s vg00/thinvol --name thinsnap
Creates a thin snapshot volume of read-only inactive volume "origin"
which then becomes the thin external origin for the thin snapshot volume in
vg00 that will use an existing thin pool "vg00/pool":
lvcreate -s --thinpool vg00/pool origin
Create a cache pool LV that can later be used to cache one logical volume.
lvcreate --type cache-pool -L 1G -n my_lv_cachepool vg /dev/fast1
If there is an existing cache pool LV, create the large slow device (i.e. the
origin LV) and link it to the supplied cache pool LV, creating a cache LV.
lvcreate --type cache -L 100G -n my_lv vg/my_lv_cachepool /dev/slow1
If there is an existing logical volume, create the small and fast cache pool LV
and link it to the supplied existing logical volume (i.e. the origin LV),
creating a cache LV.
lvcreate --type cache -L 1G -n my_lv_cachepool vg/my_lv /dev/fast1
SEE ALSO¶
lvm(8),
lvm.conf(5),
lvmcache(7),
lvmthin(7),
lvconvert(8),
lvchange(8),
lvextend(8),
lvreduce(8),
lvremove(8),
lvrename(8) lvs(8),
lvscan(8),
vgcreate(8)