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Linux / Unix Command: lvcreate
Command Library

NAME

lvcreate - create a logical volume in an existing volume group  

SYNOPSIS

lvcreate [-A|--autobackup {y|n}] [-C|--contiguous {y|n}] [-d|--debug] [-h|--help] [-i|--stripes StripesI] [-I|--stripesize StripeSizeI]] {-l|--extents LogicalExtentsNumber| -L|--size LogicalVolumeSize[kKmMgGtT]} [-n|--name LogicalVolumeName] [-p|--permission{r|rw}] [-r|--readahead ReadAheadSectors] [-v|--verbose][-Z|--zero{y|n}] VolumeGroupName [PhysicalVolumePath...]


lvcreate {-l/--extents LogicalExtentsNumber |
 -L/--size LogicalVolumeSize[kKmMgGtT]} [-c/--chunksize ChunkSize] -s/--snapshot -n/--name SnapshotLogicalVolumeName OriginalLogicalVolumePath [PhysicalVolumePath...]  

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), e2fsadm(8) ).
The second form supports the creation of snapshot logical volumes which keep the contents of the original logical volume for backup purposes.  

OPTIONS

-A, --autobackup {y|n}
Controls automatic backup of VG metadata after the change ( see vgcfgbackup(8) ).
Default is yes.
-c, --chunksize ChunkSize
Power of 2 chunk size for the snapshot logical volume between 4k and 1024k.
-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.
-d, --debug
Enables additional debugging output (if compiled with DEBUG).
-h, --help
Print a usage message on standard output and exit successfully.
-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)
-l, --extents LogicalExtentsNumber
Gives the number of logical extents to allocate for the new logical volume.
-L, --size LogicalVolumeSize[kKmMgGtT]
Gives the size to allocate for the new logical volume. A size suffix of K for kilobytes, M for megabytes, G for gigabytes or T for terabytes is optional.
Default unit is megabytes.
-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/w
Set access permissions to read only or read and write.
Default is read and write.
-r, --readahead ReadAheadSectors
Set read ahead sector count of this logical volume to a value between 2 and 120.
-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.
-v, --verbose
Gives verbose information about lvcreate's activities.
-Z, --zero y/n
Controls zeroing of the first KB of data in the new logical volume.
Default is yes.


Warning: trying to mount an unzeroed logical volume can cause the system to hang.

 

Examples

"lvcreate -i 3 -I 8 -L 100 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 --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 is updated.  


Important: Use the man command (% man) to see how a command is used on your particular computer.

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