lvm2/man/lvcreate.8_des

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
(\fBvgextend\fP(8)), or existing LVs can be reduced or removed
(\fBlvremove\fP(8), \fBlvreduce\fP(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
\fBlvmraid\fP(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
\fBlvmthin\fP(7) and \fBlvmcache\fP(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.
.SS Usage notes
In the usage section below, \fB--size\fP \fISize\fP can be replaced
with \fB--extents\fP \fINumber\fP. See descriptions in the options section.

In the usage section below, \fB--name\fP 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.