PVCREATE(8) System Manager's Manual PVCREATE(8)
NAME
pvcreate -- Initialize physical volume(s) for use by LVM
SYNOPSIS
pvcreate position_args
[ option_args ]
DESCRIPTION
pvcreate initializes a Physical Volume (PV) on a device so the device
is recognized as belonging to LVM. This allows the PV to be used in a
Volume Group (VG). An LVM disk label is written to the device, and LVM
metadata areas are initialized. A PV can be placed on a whole device
or partition.
Use vgcreate(8) to create a new VG on the PV, or vgextend(8) to add the
PV to an existing VG. Use pvremove(8) to remove the LVM disk label
from the device.
The force option will create a PV without confirmation. Repeating the
force option (-ff) will forcibly create a PV, overriding checks that
normally prevent it, e.g. if the PV is already in a VG.
Metadata location, size, and alignment
The LVM disk label begins 512 bytes from the start of the device, and
is 512 bytes in size.
The LVM metadata area begins at an offset (from the start of the
device) equal to the page size of the machine creating the PV (often 4
KiB.) The metadata area contains a 512 byte header and a multi-KiB cir-
cular buffer that holds text copies of the VG metadata.
With default settings, the first physical extent (PE), which contains
LV data, is 1 MiB from the start of the device. This location is con-
trolled by default_data_alignment in lvm.conf, which is set to 1 (MiB)
by default. The pe_start will be a multiple of this many MiB. This
location can be checked with:
pvs -o pe_start PV
The size of the LVM metadata area is the space between the the start of
the metadata area and the first PE. When metadata begins at 4 KiB and
the first PE is at 1024 KiB, the metadata area size is 1020 KiB. This
can be checked with:
pvs -o mda_size PV
The mda_size cannot be increased after pvcreate, so if larger metadata
is needed, it must be set during pvcreate. Two copies of the VG meta-
data must always fit within the metadata area, so the maximum VG meta-
data size is around half the mda_size. This can be checked with:
vgs -o mda_free VG
A larger metadata area can be set with --metadatasize. The resulting
mda_size may be larger than specified due to default_data_alignment
placing pe_start on a MiB boundary, and the fact that the metadata area
extends to the first PE. With metadata starting at 4 KiB and
default_data_alignment 1 (MiB), setting --metadatasize 2048k results in
pe_start of 3 MiB and mda_size of 3068 KiB. Alternatively, --metadata-
size 2044k results in pe_start at 2 MiB and mda_size of 2044 KiB.
The alignment of pe_start described above may be automatically overrid-
den based on md device properties or device i/o properties reported in
sysfs. These automatic adjustments can be enabled/disabled using
lvm.conf settings md_chunk_alignment and data_alignment_offset_detec-
tion.
To use a different pe_start alignment, use the --dataalignment option.
The --metadatasize option would also typically be used in this case
because the metadata area size also determines the location of
pe_start. When using these two options together, pe_start is calcu-
lated as: metadata area start (page size), plus the specified --meta-
datasize, rounded up to the next multiple of --dataalignment. With
metadata starting at 4 KiB, --metadatasize 2048k, and --dataalignment
128k, pe_start is 2176 KiB and mda_size is 2172 KiB. The pe_start of
2176 KiB is the nearest even multiple of 128 KiB that provides at least
2048 KiB of metadata space. Always check the resulting alignment and
metadata size when using these options.
To shift an aligned pe_start value, use the --dataalignmentoffset
option. The pe_start alignment is calculated as described above, and
then the value specified with --dataalignmentoffset is added to produce
the final pe_start value.
USAGE
pvcreate PV ...
[ -f|--force ]
[ -M|--metadatatype lvm2 ]
[ -u|--uuid String ]
[ -Z|--zero y|n ]
[ --dataalignment Size[k|UNIT] ]
[ --dataalignmentoffset Size[k|UNIT] ]
[ --bootloaderareasize Size[m|UNIT] ]
[ --labelsector Number ]
[ --[pv]metadatacopies 0|1|2 ]
[ --metadatasize Size[m|UNIT] ]
[ --metadataignore y|n ]
[ --norestorefile ]
[ --setphysicalvolumesize Size[m|UNIT] ]
[ --reportformat basic|json ]
[ --restorefile String ]
[ COMMON_OPTIONS ]
Common options for lvm:
[ -d|--debug ]
[ -h|--help ]
[ -q|--quiet ]
[ -t|--test ]
[ -v|--verbose ]
[ -y|--yes ]
[ --commandprofile String ]
[ --config String ]
[ --devices PV ]
[ --devicesfile String ]
[ --driverloaded y|n ]
[ --journal String ]
[ --lockopt String ]
[ --longhelp ]
[ --nohints ]
[ --nolocking ]
[ --profile String ]
[ --version ]
OPTIONS
--bootloaderareasize Size[m|UNIT]
Reserve space for the bootloader between the LVM metadata area
and the first PE. The bootloader area is reserved for bootload-
ers to embed their own data or metadata; LVM will not use it.
The bootloader area begins where the first PE would otherwise be
located. The first PE is moved out by the size of the boot-
loader area, and then moved out further if necessary to match
the data alignment. The start of the bootloader area is always
aligned, see also --dataalignment and --dataalignmentoffset. The
bootloader area may be larger than requested due to the align-
ment, but it's never less than the requested size. To see the
bootloader area start and size of an existing PV use pvs -o
+pv_ba_start,pv_ba_size.
--commandprofile String
The command profile to use for command configuration. See
lvm.conf(5) for more information about profiles.
--config String
Config settings for the command. These override lvm.conf(5) set-
tings. The String arg uses the same format as lvm.conf(5), or
may use section/field syntax. See lvm.conf(5) for more informa-
tion about config.
--dataalignment Size[k|UNIT]
Align the start of a PV data area with a multiple of this num-
ber. To see the location of the first Physical Extent (PE) of
an existing PV, use pvs -o +pe_start. In addition, it may be
shifted by an alignment offset, see --dataalignmentoffset. Also
specify an appropriate PE size when creating a VG.
--dataalignmentoffset Size[k|UNIT]
Shift the start of the PV data area by this additional offset.
-d|--debug ...
Set debug level. Repeat from 1 to 6 times to increase the detail
of messages sent to the log file and/or syslog (if configured).
--devices PV
Restricts the devices that are visible and accessible to the
command. Devices not listed will appear to be missing. This
option can be repeated, or accepts a comma separated list of
devices. This overrides the devices file.
--devicesfile String
A file listing devices that LVM should use. The file must exist
in /etc/lvm/devices/ and is managed with the lvmdevices(8) com-
mand. This overrides the lvm.conf(5) devices/devicesfile and
devices/use_devicesfile settings.
--driverloaded y|n
If set to no, the command will not attempt to use device-mapper.
For testing and debugging.
-f|--force ...
Override various checks, confirmations and protections. Use
with extreme caution.
-h|--help
Display help text.
--journal String
Record information in the systemd journal. This information is
in addition to information enabled by the lvm.conf log/journal
setting. command: record information about the command. out-
put: record the default command output. debug: record full com-
mand debugging.
--labelsector Number
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.
--lockopt String
Used to pass options for special cases to lvmlockd. See lvm-
lockd(8) for more information.
--longhelp
Display long help text.
--metadataignore y|n
Specifies the metadataignore property of a PV. If yes, metadata
areas on the PV are ignored, and lvm will not store metadata in
the metadata areas of the PV. If no, lvm will store metadata on
the PV.
--metadatasize Size[m|UNIT]
The approximate amount of space used for each VG metadata area.
The size may be rounded.
-M|--metadatatype lvm2
Specifies the type of on-disk metadata to use. lvm2 (or just 2)
is the current, standard format. lvm1 (or just 1) is no longer
used.
--nohints
Do not use the hints file to locate devices for PVs. A command
may read more devices to find PVs when hints are not used. The
command will still perform standard hint file invalidation where
appropriate.
--nolocking
Disable locking.
--norestorefile
In conjunction with --uuid, this allows a uuid to be specified
without also requiring that a backup of the metadata be pro-
vided.
--profile String
An alias for --commandprofile or --metadataprofile, depending on
the command.
--[pv]metadatacopies 0|1|2
The number of metadata areas to set aside on a PV for storing VG
metadata. When 2, one copy of the VG metadata is stored at the
front of the PV and a second copy is stored at the end. When 1,
one copy of the VG metadata is stored at the front of the PV.
When 0, no copies of the VG metadata are stored on the given PV.
This may be useful in VGs containing many PVs (this places limi-
tations on the ability to use vgsplit later.)
-q|--quiet ...
Suppress output and log messages. Overrides --debug and --ver-
bose. Repeat once to also suppress any prompts with answer
'no'.
--reportformat basic|json
Overrides current output format for reports which is defined
globally by the report/output_format setting in lvm.conf(5).
basic is the original format with columns and rows. If there is
more than one report per command, each report is prefixed with
the report name for identification. json produces report output
in JSON format. See lvmreport(7) for more information.
--restorefile String
In conjunction with --uuid, this reads the file (produced by
vgcfgbackup), extracts the location and size of the data on the
PV, and ensures that the metadata produced by the program is
consistent with the contents of the file, i.e. the physical
extents will be in the same place and not be overwritten by new
metadata. This provides a mechanism to upgrade the metadata for-
mat or to add/remove metadata areas. Use with care.
--setphysicalvolumesize Size[m|UNIT]
Overrides the automatically detected size of the PV. Use with
care, or prior to reducing the physical size of the device.
-t|--test
Run in test mode. Commands will not update metadata. This is
implemented by disabling all metadata writing but nevertheless
returning success to the calling function. This may lead to
unusual error messages in multi-stage operations if a tool
relies on reading back metadata it believes has changed but
hasn't.
-u|--uuid String
Specify a UUID for the device. Without this option, a random
UUID is generated. This option is needed before restoring a
backup of LVM metadata onto a replacement device; see vgcfgre-
store(8). As such, use of --restorefile is compulsory unless the
--norestorefile is used. All PVs must have unique UUIDs, and
LVM will prevent certain operations if multiple devices are seen
with the same UUID. See vgimportclone(8) for more information.
-v|--verbose ...
Set verbose level. Repeat from 1 to 4 times to increase the
detail of messages sent to stdout and stderr.
--version
Display version information.
-y|--yes
Do not prompt for confirmation interactively but always assume
the answer yes. Use with extreme caution. (For automatic no,
see -qq.)
-Z|--zero y|n
Controls if the first 4 sectors (2048 bytes) of the device are
wiped. The default is to wipe these sectors unless either or
both of --restorefile or --uuid are specified.
VARIABLES
PV Physical Volume name, a device path under /dev. For commands
managing physical extents, a PV positional arg generally accepts
a suffix indicating a range (or multiple ranges) of physical
extents (PEs). When the first PE is omitted, it defaults to the
start of the device, and when the last PE is omitted it defaults
to end. Start and end range (inclusive): PV[:PE-PE]... Start
and length range (counting from 0): PV[:PE+PE]...
String See the option description for information about the string con-
tent.
Size[UNIT]
Size is an input number that accepts an optional unit. Input
units are always treated as base two values, regardless of capi-
talization, e.g. 'k' and 'K' both refer to 1024. The default
input unit is specified by letter, followed by |UNIT. UNIT rep-
resents other possible input units: b|B is bytes, s|S is sectors
of 512 bytes, k|K is KiB, m|M is MiB, g|G is GiB, t|T is TiB,
p|P is PiB, e|E is EiB. (This should not be confused with the
output control --units, where capital letters mean multiple of
1000.)
ENVIRONMENT VARIABLES
See lvm(8) for information about environment variables used by lvm.
For example, LVM_VG_NAME can generally be substituted for a required VG
parameter.
EXAMPLES
Initialize a partition and a full device.
pvcreate /dev/sdc4 /dev/sde
If a device is a 4KiB sector drive that compensates for windows parti-
tioning (sector 7 is the lowest aligned logical block, the 4KiB sectors
start at LBA -1, and consequently sector 63 is aligned on a 4KiB bound-
ary) manually account for this when initializing for use by LVM.
pvcreate --dataalignmentoffset 7s /dev/sdb
SEE ALSO
lvm(8), lvm.conf(5), lvmconfig(8), lvmdevices(8),
pvchange(8), pvck(8), pvcreate(8), pvdisplay(8), pvmove(8),
pvremove(8), pvresize(8), pvs(8), pvscan(8),
vgcfgbackup(8), vgcfgrestore(8), vgchange(8), vgck(8), vgcreate(8),
vgconvert(8), vgdisplay(8), vgexport(8), vgextend(8), vgimport(8),
vgimportclone(8), vgimportdevices(8), vgmerge(8), vgmknodes(8),
vgreduce(8), vgremove(8), vgrename(8), vgs(8), vgscan(8), vgsplit(8),
lvcreate(8), lvchange(8), lvconvert(8), lvdisplay(8), lvextend(8),
lvreduce(8), lvremove(8), lvrename(8), lvresize(8), lvs(8), lvscan(8),
lvm-fullreport(8), lvm-lvpoll(8), lvm2-activation-generator(8),
blkdeactivate(8), lvmdump(8),
dmeventd(8), lvmpolld(8), lvmlockd(8), lvmlockctl(8), cmirrord(8),
lvmdbusd(8), fsadm(8),
lvmsystemid(7), lvmreport(7), lvmraid(7), lvmthin(7), lvmcache(7)
Red Hat, Inc. LVM TOOLS 2.03.14(2)-RHEL8 (2021-10-20) PVCREATE(8)
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