NAME¶
pvcreate — initialize a disk or partition for use by LVM
SYNOPSIS¶
pvcreate [
--commandprofile ProfileName]
[
-d|
--debug] [
-h|
--help] [
-t|
--test]
[
-v|
--verbose] [
--version]
[
-f[
f]|
--force [
--force]] [
-y|
--yes]
[
--labelsector] [
--bootloaderareasize size]
[
-M|
--metadatatype type]
[
--[
pv]
metadatacopies NumberOfCopies]
[
--metadatasize size] [
--metadataignore
{
y|
n}] [
--dataalignment alignment]
[
--dataalignmentoffset alignment_offset] [
--restorefile
file] [
--norestorefile] [
--setphysicalvolumesize
size] [
-u|
--uuid uuid] [
-Z|
--zero
{
y|
n}]
PhysicalVolume [
PhysicalVolume...]
DESCRIPTION¶
pvcreate initializes
PhysicalVolume for later use by the Logical Volume
Manager (LVM). Each
PhysicalVolume can be a disk partition, whole disk,
meta device, or loopback file. For DOS disk partitions, the partition id
should be set to 0x8e using
fdisk(8),
cfdisk(8), or a
equivalent. For
whole disk devices only the partition table must be
erased, which will effectively destroy all data on that disk. This can be done
by zeroing the first sector with:
dd if=/dev/zero of=PhysicalVolume bs=512 count=1
Continue with
vgcreate(8) to create a new volume group on
PhysicalVolume, or
vgextend(8) to add
PhysicalVolume to
an existing volume group.
OPTIONS¶
See
lvm(8) for common options.
- -f, --force
- Force the creation without any confirmation. You can not recreate
(reinitialize) a physical volume belonging to an existing volume group. In
an emergency you can override this behaviour with -ff.
- -u, --uuid uuid
- Specify the uuid for the device. Without this option, pvcreate(8)
generates a random uuid. All of your physical volumes must have unique
uuids. You need to use this option before restoring a backup of LVM
metadata onto a replacement device - see vgcfgrestore(8). As such,
use of --restorefile is compulsory unless the
--norestorefile is used.
- -y, --yes
- Answer yes to all questions.
- -Z, --zero
{y|n}
- Whether or not the first 4 sectors (2048 bytes) of the device should be
wiped. If this option is not given, the default is to wipe these sectors
unless either or both of the --restorefile or --uuid options
were specified.
LVM2 introduces a new format for storing metadata on disk. This new format is
more efficient and resilient than the format the original version of LVM used
and offers the advanced user greater flexibility and control.
The new format may be selected on the command line with
-M2 or by setting
format = "lvm2" in the
global section of
lvm.conf(5). Each physical volume in the same volume group must use the
same format, but different volume groups on a machine may use different
formats simultaneously: the tools can handle both formats. Additional formats
can be added as shared libraries.
Additional tools for manipulating the locations and sizes of metadata areas will
be written in due course. Use the verbose/debug options on the tools to see
where the metadata areas are placed.
- --metadatasize size
- The approximate amount of space to be set aside for each metadata area.
(The size you specify may get rounded.)
- --dataalignment alignment
- Align the start of the data to a multiple of this number. You should also
specify an appropriate PhysicalExtentSize when creating the Volume
Group with vgcreate.
To see the location of the first Physical Extent of an existing Physical
Volume use pvs -o +pe_start . It will be a multiple of the
requested alignment. In addition it may be shifted by
alignment_offset from data_alignment_offset_detection (if
enabled in lvm.conf(5)) or --dataalignmentoffset.
- --dataalignmentoffset alignment_offset
- Shift the start of the data area by this additional
alignment_offset.
- --[pv]metadatacopies
NumberOfCopies
- The number of metadata areas to set aside on each PV. Currently this can
be 0, 1 or 2. If set to 2, two copies of the volume group metadata are
held on the PV, one at the front of the PV and one at the end. If set to 1
(the default), one copy is kept at the front of the PV (starting in the
5th sector). If set to 0, no copies are kept on this PV - you might wish
to use this with VGs containing large numbers of PVs. But if you do this
and then later use vgsplit(8) you must ensure that each VG is still
going to have a suitable number of copies of the metadata after the
split!
- --metadataignore
{y|n}
- Ignore or un-ignore metadata areas on this physical volume. The default is
"n". This setting can be changed with pvchange. If
metadata areas on a physical volume are ignored, LVM will not store
metadata in the metadata areas present on this Physical Volume. Metadata
areas cannot be created or extended after Logical Volumes have been
allocated on the device. If you do not want to store metadata on this
device, it is still wise always to allocate a metadata area in case you
need it in the future and to use this option to instruct LVM2 to ignore
it.
- --restorefile file
- In conjunction with --uuid, this extracts the location and size of
the data on the PV from the file (produced by vgcfgbackup) and
ensures that the metadata that the program produces is consistent with the
contents of the file i.e. the physical extents will be in the same place
and not get overwritten by new metadata. This provides a mechanism to
upgrade the metadata format or to add/remove metadata areas. Use with
care. See also vgconvert(8).
- --norestorefile
- In conjunction with --uuid, this allows a uuid to be
specified without also requiring that a backup of the metadata be
provided.
- --labelsector sector
- By default the PV is labelled with an LVM2 identifier in its second sector
(sector 1). This lets you use a different sector near the start of the
disk (between 0 and 3 inclusive - see LABEL_SCAN_SECTORS in the source).
Use with care.
- --bootloaderareasize size
- Create a separate bootloader area of specified size besides PV's data
area. The bootloader area is an area of reserved space on the PV from
which LVM2 will not allocate any extents and it's kept untouched. This is
primarily aimed for use with bootloaders to embed their own data or
metadata. The start of the bootloader area is always aligned, see also
--dataalignment and --dataalignmentoffset. The bootloader
area size may eventually end up increased due to the alignment, but it's
never less than the size that is requested. To see the bootloader area
start and size of an existing Physical Volume use pvs -o
+pv_ba_start,pv_ba_size.
- --setphysicalvolumesize size
- Overrides the automatically-detected size of the PV. Use with care.
Examples¶
Initialize partition #4 on the third SCSI disk and the entire fifth SCSI disk
for later use by LVM:
pvcreate /dev/sdc4 /dev/sde
If the 2nd SCSI disk is a 4KiB sector drive that compensates for windows
partitioning (sector 7 is the lowest aligned logical block, the 4KiB sectors
start at LBA -1, and consequently sector 63 is aligned on a 4KiB boundary)
manually account for this when initializing for use by LVM:
pvcreate --dataalignmentoffset 7s /dev/sdb
SEE ALSO¶
lvm.conf(5),
lvm(8),
vgcreate(8),
vgextend(8),
lvcreate(8),
cfdisk(8),
fdisk(8),
losetup(8),
mdadm(8),
vgcfgrestore(8),
vgconvert(8)