Provided by: lvm2_2.02.133-1ubuntu10_amd64 
NAME
lvcreate - create a logical volume in an existing volume group
SYNOPSIS
lvcreate [-a|--activate [a][e|l|s]{y|n}] [--addtag Tag] [--alloc AllocationPolicy]
[-A|--autobackup {y|n}] [-H|--cache] [--cachemode {passthrough|writeback|writethrough}]
[--cachepolicy policy] [--cachepool CachePoolLogicalVolume] [--cachesettings key=value]
[-c|--chunksize ChunkSize] [--commandprofile ProfileName] [-C|--contiguous {y|n}]
[-d|--debug] [--discards {ignore|nopassdown|passdown}] [--errorwhenfull {y|n}]
[{-l|--extents LogicalExtentsNumber[%{FREE|PVS|VG}] | -L|--size LogicalVolumeSize}
[-i|--stripes Stripes [-I|--stripesize StripeSize]]] [-h|-?|--help]
[-K|--ignoreactivationskip] [--ignoremonitoring] [--minor minor [-j|--major major]]
[--metadataprofile ProfileName] [-m|--mirrors Mirrors [--corelog|--mirrorlog
{disk|core|mirrored}] [--nosync] [-R|--regionsize MirrorLogRegionSize]] [--monitor {y|n}]
[-n|--name LogicalVolume] [--noudevsync] [-p|--permission {r|rw}] [-M|--persistent {y|n}]
[--poolmetadatasize MetadataVolumeSize] [--poolmetadataspare {y|n}]
[--[raid]maxrecoveryrate Rate] [--[raid]minrecoveryrate Rate] [-r|--readahead
{ReadAheadSectors|auto|none}] [-k|--setactivationskip {y|n}] [-s|--snapshot]
[-V|--virtualsize VirtualSize] [-t|--test] [-T|--thin] [--thinpool ThinPoolLogicalVolume]
[--type SegmentType] [-v|--verbose] [-W|--wipesignatures {y|n}] [-Z|--zero {y|n}]
[VolumeGroup[/{ExternalOrigin|Origin|Pool}LogicalVolumeName
[PhysicalVolumePath[:PE[-PE]]...]]
lvcreate [-l|--extents LogicalExtentsNumber[%{FREE|ORIGIN|PVS|VG}] | -L|--size
LogicalVolumeSize] [-c|--chunksize ChunkSize] [--commandprofile ProfileName]
[--noudevsync] [--ignoremonitoring] [--metadataprofile ProfileName] [--monitor {y|n}]
[-n|--name SnapshotLogicalVolume] -s|--snapshot|-H|--cache
{[VolumeGroup/]OriginalLogicalVolume [-V|--virtualsize VirtualSize]}
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 [a][l|e|s]{y|n}
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 of active origin can only be created in the active state so -an
cannot be used with --type snapshot. This does not apply to thin volume snapshots,
which are by default created with flag to skip their activation (-ky). 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.
-H|--cache
Creates cache or cache pool logical volume. Specifying the optional argument
--extents or --size will cause the creation of the cache logical volume. When the
Volume group name is specified together with existing logical volume name which is
NOT a cache pool name, such volume is treated as cache origin volume and cache pool
is created. In this case the --extents or --size is used to specify size of cache
pool volume. 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.
--cachemode {passthrough|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.
--cachepolicy policy
Only applicable to cached LVs; see also lvmcache(7). Sets the cache policy. mq is
the basic policy name. smq is more advanced version available in newer kernels.
--cachepool CachePoolLogicalVolume{Name|Path}
Specifies the name of cache pool volume name. The other way to specify pool name is
to append name to Volume group name argument.
--cachesettings key=value
Only applicable to cached LVs; see also lvmcache(7). Sets the cache tunable
settings. In most use-cases, default values should be adequate. Special string
value default switches setting back to its default kernel value and removes it from
the list of settings stored in lvm2 metadata.
-c|--chunksize ChunkSize[b|B|s|S|k|K|m|M|g|G]
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 4KiB.
For cache pools the value must a multiple of 32KiB between 32KiB and 1GiB. The
default is 64KiB.
For thin pools the value must be a multiple of 64KiB between 64KiB and 1GiB.
Default value starts with 64KiB and grows up to fit the pool metadata size within
128MiB, if the pool metadata size is not specified. See lvm.conf(5) setting
allocation/thin_pool_chunk_size_policy to select different calculation policy.
Thin pool target version <1.4 requires this value to be a power of 2. 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.
--corelog
This is shortcut for option --mirrorlog core.
--discards {ignore|nopassdown|passdown}
Sets discards behavior for thin pool. Default is passdown.
--errorwhenfull {y|n}
Configures thin pool behaviour when data space is exhausted. Default is no.
Device will queue I/O operations until target timeout (see dm-thin-pool kernel
module option no_space_timeout) expires. Thus configured system has a time to i.e.
extend the size of thin pool data device. When set to yes, the I/O operation is
immeditelly errored.
-K|--ignoreactivationskip
Ignore the flag to skip Logical Volumes during activation. Use --setactivationskip
option to set or reset activation skipping flag persistently for logical volume.
--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 number of physical extents to be allocated (including extents used by any
mirrors, for example).
-j|--major major
Sets the major number. Major numbers are not supported with pool volumes. This
option is supported only on older systems (kernel version 2.4) and is ignored on
modern Linux systems where major numbers are dynamically assigned.
--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.
--minor minor
Sets the minor number. Minor numbers are not supported with pool volumes.
-m|--mirrors mirrors
Creates a mirrored logical volume with mirrors copies. For example, specifying -m
1 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.
See lvm.conf(5) settings global/mirror_segtype_default and
global/raid10_segtype_default to configure default mirror segment type. The
options --mirrorlog and --corelog apply to the legacy "mirror" segment type only.
--mirrorlog {disk|core|mirrored}
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.
--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.
--nosync
Causes the creation of the mirror to skip the initial resynchronization.
--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.
-M|--persistent {y|n}
Set to y to make the minor number specified persistent. Pool volumes cannot have
persistent major and minor numbers. Defaults to yes only when major or minor
number is specified. Otherwise it is no.
--poolmetadatasize MetadataVolumeSize[b|B|s|S|k|K|m|M|g|G]
Sets the size of pool's metadata logical volume. Supported values are in range
between 2MiB and 16GiB for thin pool, and upto 16GiB for cache pool. The minimum
value is computed from pool's data size. Default value for thin pool 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.
--[raid]maxrecoveryrate Rate[b|B|s|S|k|K|m|M|g|G]
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[b|B|s|S|k|K|m|M|g|G]
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.
-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[b|B|s|S|k|K|m|M|g|G]
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.
-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. See
lvm.conf(5) activation/auto_set_activation_skip how to change its default
behaviour. To activate such volumes, an extra --ignoreactivationskip option must
be used. The flag is not applied during deactivation. Use lvchange
--setactivationskip command to change the skip 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.
-L|--size LogicalVolumeSize[b|B|s|S|k|K|m|M|g|G|t|T|p|P|e|E]
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.
-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.
-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 -i
3 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.
-T|--thin
Creates thin pool or thin logical volume or both. Specifying the optional argument
--size or --extents 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. Thin provisioning requires device
mapper kernel driver from kernel 3.2 or greater.
--thinpool ThinPoolLogicalVolume{Name|Path}
Specifies the name of thin pool volume name. The other way to specify pool name is
to append name to Volume group name argument.
--type SegmentType
Creates a logical volume with the specified segment type. Supported types are:
cache, cache-pool, error, linear, mirror, raid1, raid4, raid5_la, raid5_ls (=
raid5), raid5_ra, raid5_rs, raid6_nc, raid6_nr, raid6_zr (= raid6), raid10,
snapshot, striped, thin, thin-pool or zero. Segment type may have a commandline
switch alias that will enable its use. When the type is not explicitly specified
an implicit type is selected from combination of options: -H|--cache|--cachepool
(cache or cachepool), -T|--thin|--thinpool (thin or thinpool), -m|--mirrors (raid1
or mirror), -s|--snapshot|-V|--virtualsize (snapshot or thin), -i|--stripes
(striped). Default segment type is linear.
-V|--virtualsize VirtualSize[b|B|s|S|k|K|m|M|g|G|t|T|p|P|e|E]
Creates a thinly provisioned device or a sparse device of the given size (in MiB by
default). See lvm.conf(5) settings global/sparse_segtype_default to configure
default sparse segment type. See lvmthin(7) for more info about thin provisioning
support. Anything written to a sparse snapshot will be returned when reading from
it. Reading from other areas of the device will return blocks of zeros. Virtual
snapshot (sparse 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. Snapshot COW volumes are always zeroed. Logical volume is not zeroed if the
read only flag is set.
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 --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), blkid(8)