lvcreate - create a logical volume in an existing volume group
lvcreate [--addtag Tag] [--alloc AllocationPolicy] [-A|--autobackup y|n]
[-C|--contiguous y|n] [-d|--debug] [-h|-?|--help] [-i|--stripes Stripes
[-I|--stripesize StripeSize]] {-l|--extents
LogicalExtentsNumber[%{VG|PVS|FREE}] |
-L|--size LogicalVolumeSize[kKmMgGtT]} [-M|--persistent y|n] [--minor minor]
[-m|--mirrors Mirrors [--nosync] [--mirrorlog {disk|core}] [--corelog]
[-R|--regionsize MirrorLogRegionSize]] [-n|--name LogicalVolumeName]
[-p|--permission r|rw] [-r|--readahead ReadAheadSectors|auto|none] [-t|--test]
[-v|--verbose] [-Z|--zero y|n] VolumeGroupName [PhysicalVolumePath...]
lvcreate {-l|--extents LogicalExtentsNumber[%{VG|FREE}] |
-L|--size LogicalVolumeSize[kKmMgGtT]} [-c|--chunksize ChunkSize]
-s|--snapshot -n|--name SnapshotLogicalVolumeName
OriginalLogicalVolumePath
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) ).
The second form supports the creation of snapshot logical volumes which keep the
contents of the original logical volume for backup purposes.
See lvm for common options.
- -c, --chunksize ChunkSize
- Power of 2 chunk size for the snapshot logical volume between 4k and
512k.
- -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.
- -i, --stripes Stripes
- Gives the number of stripes. This is equal to the number of physical
volumes to scatter the logical volume.
- -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.
- -l, --extents LogicalExtentsNumber[%{VG|PVS|FREE}]
- Gives the number of logical extents to allocate for the new logical
volume. This can also be expressed as a percentage of the total space in
the Volume Group with the suffix %VG, of the remaining free space in the
Volume Group with the suffix %FREE, or of the remaining free space for the
specified PhysicalVolume(s) with the suffix %PVS,
- -L, --size LogicalVolumeSize[kKmMgGtTpPeE]
- Gives the size to allocate for the new logical volume. A size suffix of 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.
- --minor minor
- Set the minor number.
- -M, --persistent y|n
- Set to y to make the minor number specified persistent.
- -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.
The optional argument --mirrorlog specifies the type of log to
be used. 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 again each time the device is activated,
for example, after every reboot.
The optional argument --corelog is equivalent to --mirrorlog
core.
- -n, --name LogicalVolumeName
- The name for the new logical volume.
Without this option a default names of "lvol#" will be generated
where # is the LVM internal number of the logical volume.
- -p, --permission r|rw
- Set access permissions to read only or read and write.
Default is read and write.
- -r, --readahead ReadAheadSectors|auto|none
- Set 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 MB), and the mirror log
uses this granularity to track which regions are in sync.
- -s, --snapshot
- Create 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. The snapshot 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
lvdisplay(8) on the snapshot in order to check how much data is
allocated to it.
- -Z, --zero y|n
- Controls zeroing of the first KB of data in the new logical volume.
Default is yes.
Volume will not be zeroed if read only flag is set.
Snapshot volumes are zeroed always.
Warning: trying to mount an unzeroed logical volume can cause
the system to hang.
"lvcreate -i 3 -I 8 -L 100M vg00" tries to create a striped logical
volume with 3 stripes, a stripesize of 8KB and a size of 100MB in the volume
group named vg00. The logical volume name will be chosen by lvcreate.
"lvcreate -m1 -L 500M vg00" tries to create a mirror
logical volume with 2 sides with a useable size of 500 MiB. This operation
would require 3 devices - two for the mirror devices and one for the disk
log.
"lvcreate -m1 --mirrorlog core -L 500M vg00" tries to
create 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 --size 100m --snapshot --name snap
/dev/vg00/lvol1"
creates a snapshot logical volume named /dev/vg00/snap which has access to the
contents of the original logical volume named /dev/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.
lvm(8), vgcreate(8), lvremove(8), lvrename(8)
lvextend(8), lvreduce(8), lvdisplay(8), lvscan(8)