LVCREATE(8) System Manager's Manual LVCREATE(8)
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 CachePool‐
LogicalVolume] [--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 Logical‐
Volume] [--noudevsync] [-p|--permission {r|rw}] [-M|--persistent {y|n}] [--poolmetadatasize MetadataVolume‐
Size] [--poolmetadataspare {y|n}] [--[raid]maxrecoveryrate Rate] [--[raid]minrecoveryrate Rate] [-r|--reada‐
head {ReadAheadSectors|auto|none}] [--reportformat {basic|json}] [-k|--setactivationskip {y|n}] [-s|--snap‐
shot] [-V|--virtualsize VirtualSize] [-t|--test] [-T|--thin] [--thinpool ThinPoolLogicalVolume] [--type Seg‐
mentType] [-v|--verbose] [-W|--wipesignatures {y|n}] [-Z|--zero {y|n}] [VolumeGroup |
{ExternalOrigin|Origin|Pool}LogicalVolume [PhysicalVolumePath[:PE[-PE]]...]]
lvcreate [-l|--extents LogicalExtentsNumber[%{FREE|ORIGIN|PVS|VG}] | -L|--size LogicalVolumeSize] [-c|--chunk‐
size ChunkSize] [--commandprofile ProfileName] [--noudevsync] [--ignoremonitoring] [--metadataprofile Profile‐
Name] [--monitor {y|n}] [-n|--name SnapshotLogicalVolumeName] [--reportformat {basic|json}] -s|--snap‐
shot|-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 Physi‐
calVolumes, 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 log‐
ical 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 autoacti‐
vation option is used (-aay), the logical volume is activated only if it matches an item in the activa‐
tion/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.
--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. When
the size is specified with volume caching, it may not be smaller than cache pool creation chunk size
was.
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 speci‐
fied. 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 alloca‐
tion 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}]
Specifies the size of the new LV in logical extents. The number of physical extents allocated may be
different, and depends on the LV type. Certain LV types require more physical extents for data redun‐
dancy or metadata. An alternate syntax allows the size to be determined indirectly as a percentage of
the size of a related VG, LV, or set of PVs. The suffix %VG denotes the total size of the VG, the suf‐
fix %FREE the remaining free space in the VG, and the suffix %PVS the free space in the specified Phys‐
ical Volumes. For a snapshot, the size can be expressed as a percentage of the total size of the Ori‐
gin Logical Volume with the suffix %ORIGIN (100%ORIGIN provides space for the whole origin). When
another profile attached, the logical volume profile is preferred. See lvm.conf(5) for more informa‐
tion 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 LV 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 mirrored
RaidLV.
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.
Note the current maxima for mirrors are 7 for "mirror" providing 8 mirror legs and 9 for "raid1" pro‐
viding 10 legs.
--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 log‐
ical 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 accord‐
ing 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 mirror, raid1, raid4, raid5 and raid10 to skip the initial resynchronization.
In case of mirror, raid1 and raid10, any data written afterwards will be mirrored, but the original
contents will not be copied. In case of raid4 and raid5, no parity blocks will be written, though any
data written afterwards will cause parity blocks to be stored.
This is useful for skipping a potentially long and resource intensive initial sync of an empty mir‐
ror/raid1/raid4/raid5 and raid10 LV.
This option is not valid for raid6, because raid6 relies on proper parity (P and Q Syndromes) being
created during initial synchronization in order to reconstruct proper user date in case of device fail‐
ures.
-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). To work with a thin pool,
there should be at least 25% of free space when the size of metadata is smaller then 16MiB, or at least
4MiB of free space otherwise. 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_activa‐
tion_skip how to change its default behaviour. To activate such volumes, an extra --ignoreactivation‐
skip 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.
sion 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 data. When creating a RAID 4/5/6 logical volume, the extra devices which are necessary for par‐
ity are internally accounted for. Specifying -i 3 would cause 3 devices for striped and RAID 0 logical
volumes, 4 devices for RAID 4/5, 5 devices for RAID 6 and 6 devices for RAID 10. Alternatively, RAID 0
will stripe across 2 devices, RAID 4/5 across 3 PVs, RAID 6 across 5 PVs and RAID 10 across 4 PVs in
the volume group if the -i argument is omitted. In order to stripe across all PVs of the VG if the -i
argument is omitted, set raid_stripe_all_devices=1 in the allocation section of lvm.conf (5) or add
--config allocation/raid_stripe_all_devices=1
to the command.
Note the current maxima for stripes depend on the created RAID type. For raid10, the maximum of
stripes is 32, for raid0, it is 64, for raid4/5, it is 63 and for raid6 it is 62.
See the --nosync option to optionally avoid initial syncrhonization of RaidLVs.
Two implementations of basic striping are available in the kernel. The original device-mapper imple‐
mentation is the default and should normally be used. The alternative implementation using MD, avail‐
able since version 1.7 of the RAID device-mapper kernel target (kernel version 4.2) is provided to
facilitate the development of new RAID features. It may be accessed with --type raid0[_meta], but is
best avoided at present because of assorted restrictions on resizing and converting such devices.
-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 --virtual‐
size 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, raid0, 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). The 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
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 con‐
tents 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 vol‐
ume 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 alloca‐
tion 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
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 ori‐
gin 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)
Sistina Software UK LVM TOOLS 2.02.166(2)-RHEL7 (2016-11-16) LVCREATE(8)
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