lvcreate creates a new LV in a VG. For standard LVs, this
requires allocating logical extents from the VG's free physical
extents. If there is not enough free space, the VG can be
extended with other PVs (vgextend(8)), or existing LVs can be
reduced or removed (lvremove(8), lvreduce(8)).
To control which PVs a new LV will use, specify one or more PVs
as position args at the end of the command line. lvcreate will
allocate physical extents only from the specified PVs.
lvcreate can also create snapshots of existing LVs, e.g. for
backup purposes. The data in a new snapshot LV represents the
content of the original LV from the time the snapshot was
created.
RAID LVs can be created by specifying an LV type when creating
the LV (see lvmraid(7)). Different RAID levels require different
numbers of unique PVs be available in the VG for allocation.
Thin pools (for thin provisioning) and cache pools (for caching)
are represented by special LVs with types thin-pool and
cache-pool (see lvmthin(7) and lvmcache(7)). The pool LVs are not
usable as standard block devices, but the LV names act as
references to the pools.
Thin LVs are thinly provisioned from a thin pool, and are created
with a virtual size rather than a physical size. A cache LV is
the combination of a standard LV with a cache pool, used to cache
active portions of the LV to improve performance.
VDO LVs are also provisioned volumes from a VDO pool, and are
created with a virtual size rather than a physical size (see
lvmvdo(7)).
Usage notes
In the usage section below, --size Size can be replaced with
--extents Number. See descriptions in the options section.
In the usage section below, --name is omitted from the required
options, even though it is typically used. When the name is not
specified, a new LV name is generated with the "lvol" prefix and
a unique numeric suffix.
In the usage section below, when creating a pool and the name is
omitted the new LV pool name is generated with the "vpool" for
vdo-pools for prefix and a unique numeric suffix.
Pool name can be specified together with VG name i.e.:
vg00/mythinpool.
