man
8 LVMDEVICES
LVMDEVICES(8) System Manager's Manual LVMDEVICES(8)
NAME
lvmdevices -- Manage the devices file
SYNOPSIS
lvmdevices option_args
[ option_args ]
--adddev PV
--addpvid String
--check
--commandprofile String
--config String
-d|--debug
--deldev String
--delnotfound
--delpvid String
--deviceidtype String
--devices PV
--devicesfile String
--driverloaded y|n
-h|--help
--journal String
--lockopt String
--longhelp
--nohints
--nolocking
--profile String
-q|--quiet
--refresh
-t|--test
--update
-v|--verbose
--version
-y|--yes
DESCRIPTION
The LVM devices file lists devices that lvm can use. The default file
is /etc/lvm/devices/system.devices, and the lvmdevices(8) command is
used to add or remove device entries. If the file does not exist, or
if lvm.conf includes use_devicesfile=0, then lvm will not use a devices
file.
To use a device with lvm, add it to the devices file with the command
lvmdevices --adddev, and to prevent lvm from seeing or using a device,
remove it from the devices file with lvmdevices --deldev. The vgim-
portdevices(8) command adds all PVs from a VG to the devices file, and
updates the VG metadata to include device IDs of the PVs.
Commands that add new devices to the devices file necessarily look out-
side the existing devices file to find the devices being added. pvcre-
ate, vgcreate, and vgextend also look outside the devices file to cre-
ate new PVs and add those PVs to the devices file.
LVM records devices in the devices file using hardware-specific IDs,
such as the WWID, and attempts to use subsystem-specific IDs for vir-
tual device types (which also aim to be as unique and stable as possi-
ble.) These device IDs are also written in the VG metadata. When no
hardware or virtual ID is available, lvm falls back using the unstable
device name as the device ID. When devnames are used as IDs, lvm per-
forms extra scanning to find devices if their devname changes, e.g. af-
ter reboot.
When proper device IDs are used, an lvm command will not look at de-
vices outside the devices file, but when devnames are used as a fall-
back, lvm will scan devices outside the devices file to locate PVs on
renamed devices. A config setting search_for_devnames can be used to
control the scanning for renamed devname entries.
Related to the devices file, the command option --devices <devnames>
allows a list of devices to be specified for the command to use, over-
riding the devices file. The listed devices act as a sort of devices
file in terms of limiting which devices lvm will see and use. Devices
that are not listed will appear to be missing to the lvm command.
Multiple devices files can be kept in /etc/lvm/devices, which allows
lvm to be used with different sets of devices. For example, system de-
vices do not need to be exposed to a specific application, and the ap-
plication can use lvm on its own devices that are not exposed to the
system. The option --devicesfile <filename> is used to select the de-
vices file to use with the command. Without the option set, the de-
fault system devices file is used.
Setting --devicesfile "" causes lvm to not use a devices file.
With no devices file, lvm will use any device on the system, and ap-
plies the filter to limit the full set of system devices. With a de-
vices file, the regex filter is not used, and the filter settings in
lvm.conf or the command line are ignored. The vgimportdevices command
is one exception which does apply the regex filter when looking for a
VG to import.
If a devices file exists, lvm will use it, even if it's empty. An
empty devices file means lvm will see no devices.
If the system devices file does not yet exist, the pvcreate or vgcreate
commands will create it if they see no existing VGs on the system.
lvmdevices --addev and vgimportdevices will always create a new devices
file if it does not yet exist.
It is recommended to use lvm commands to make changes to the devices
file to ensure proper updates.
The device ID and device ID type are included in the VG metadata and
can be reported with pvs -o deviceid,deviceidtype. (Note that the
lvmdevices command does not update VG metadata, but subsequent lvm com-
mands modifying the metadata will include the device ID.)
Possible device ID types are:
o sys_wwid uses the wwid reported by the wwid sysfs file. This is the
first choice.
o wwid_naa uses the naa wwid decoded from the vpd_pg83 sysfs file.
o wwid_eui uses the eui wwid decoded from the vpd_pg83 sysfs file.
o wwid_t10 uses the t10 wwid decoded from the vpd_pg83 sysfs file.
o sys_serial uses the serial number reported by the serial sysfs file
or the vpd_pg80 file. A serial number is used if no wwid is avail-
able.
o mpath_uuid is used for dm multipath devices, reported by sysfs.
o crypt_uuid is used for dm crypt devices, reported by sysfs.
o md_uuid is used for md devices, reported by sysfs.
o lvmlv_uuid is used if a PV is placed on top of an lvm LV, reported by
sysfs.
o loop_file is used for loop devices, the backing file name reported by
sysfs.
o devname the device name is used if no other type applies.
The default choice for device ID type can be overridden using lvmde-
vices --addev --deviceidtype <type>. If the specified type is avail-
able for the device it will be used, otherwise the device will be added
using the type that would otherwise be chosen.
LVM commands run by dmeventd will use the devices file /etc/lvm/de-
vices/dmeventd.devices if it exists, otherwise system.devices is used.
VGs that require the dmeventd service should be included in system.de-
vices, even if they are included in dmeventd.devices.
Device ID refresh
A machine identifier is saved in the devices file, and is used to de-
tect when the devices file has been created by a different machine. If
the devices file was created by a different machine, it indicates that
PVs may have been copied or restored onto new devices on a new machine.
In this case, lvm will search for the PVs listed in system.devices on
new devices. If found, the device IDs will be updated in system.de-
vices for the existing PVIDs (assuming the original device IDs are also
no longer found.)
The machine identifier used in system.devices will be either the DMI
product_uuid from /sys/devices/virtual/dmi/id/product_uuid, or the
hostname from uname(2). See lvm.conf device_ids_refresh_checks to con-
figure this.
USAGE
Print devices in the devices file.
lvmdevices
[ COMMON_OPTIONS ]
--
Check the devices file and report incorrect values.
lvmdevices --check
[ --refresh ]
[ COMMON_OPTIONS ]
--
Update the devices file to fix incorrect values.
lvmdevices --update
[ --delnotfound ]
[ --refresh ]
[ COMMON_OPTIONS ]
--
Add a device to the devices file.
lvmdevices --adddev PV
[ --deviceidtype String ]
[ COMMON_OPTIONS ]
--
Remove a device from the devices file.
lvmdevices --deldev String|PV
[ --deviceidtype String ]
[ COMMON_OPTIONS ]
--
Find the device with the given PVID and add it to the devices file.
lvmdevices --addpvid String
[ --deviceidtype String ]
[ COMMON_OPTIONS ]
--
Remove the devices file entry for the given PVID.
lvmdevices --delpvid 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
--adddev PV
Add a device to the devices file.
--addpvid String
Find a device with the PVID and add the device to the devices
file.
--check
Checks the content of the devices file. Reports incorrect de-
vice names or PVIDs for entries.
--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.
-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).
--deldev String
Remove a device from the devices file. When used alone,
--deldev specifies a device name. When used with --deviceid-
type, --deldev specifies a device id.
--delnotfound
Remove devices file entries with no matching device.
--delpvid String
Remove a device with the PVID from the devices file.
--deviceidtype String
The type of device ID to use for the device. If the specified
type is available for the device, then it will override the de-
fault type that lvm would use.
--devices PV
Restricts the devices that are visible and accessible to the
command. Devices not listed will appear to be missing. This op-
tion can be repeated, or accepts a comma separated list of de-
vices. 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.
-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.
--lockopt String
Used to pass options for special cases to lvmlockd. See lvm-
lockd(8) for more information.
--longhelp
Display long help text.
--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. Use with caution, concurrent commands may pro-
duce incorrect results.
--profile String
An alias for --commandprofile or --metadataprofile, depending on
the command.
-q|--quiet ...
Suppress output and log messages. Overrides --debug and --ver-
bose. Repeat once to also suppress any prompts with answer
'no'.
--refresh
Search for missing PVs on new devices, and update the devices
file with new device IDs for the PVs if they are found on new
devices. This is useful if PVs have been moved to new devices
with new WWIDs, for example. The device ID type and name may
both change for a PV. WARNING: if a PV is detached from the
system, but a device containing a clone or snapshot of that PV
is present, then refresh would replace the correct device ID
with the clone/snapshot device ID, and lvm would begin using the
wrong device for the PV. Use deldev/adddev to safely change a PV
device ID in this scenario.
-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 un-
usual error messages in multi-stage operations if a tool relies
on reading back metadata it believes has changed but hasn't.
--update
Update the content of the devices file.
-v|--verbose ...
Set verbose level. Repeat from 1 to 4 times to increase the de-
tail 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.)
VARIABLES
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.
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), blkdeactivate(8), lvmdump(8),
dmeventd(8), lvmpolld(8), lvmlockd(8), lvmlockctl(8), cmirrord(8),
lvmdbusd(8), fsadm(8),
lvmsystemid(7), lvmreport(7), lvmcache(7), lvmraid(7), lvmthin(7),
lvmvdo(7), lvmautoactivation(7)
Red Hat, Inc. LVM TOOLS 2.03.28(2)-RHEL9 (2024-11-04) LVMDEVICES(8)