PVSCAN(8) System Manager's Manual PVSCAN(8)
NAME
pvscan — scan all disks for physical volumes
SYNOPSIS
pvscan [--commandprofile ProfileName] [-d|--debug] [-h|--help] [-v|--verbose] [--version] [--ignorelocking‐
failure] [-e|--exported] [-n|--novolumegroup] [--reportformat {basic|json}] [-s|--short] [-u|--uuid]
pvscan [-d|--debug] [-h|--help] --cache [-a|--activate ay] [-b|--background] [--reportformat {basic|json}]
[--major major --minor minor | DevicePath | major:minor]...
DESCRIPTION
pvscan scans all supported LVM block devices in the system for physical volumes.
Scanning with lvmetad
pvscan operates differently when used with the lvmetad(8) daemon.
Scanning disks is required to read LVM metadata and identify LVM PVs. Once read, lvmetad caches the metadata
so that LVM commands can read it without repeatedly scanning disks. This is helpful because scanning disks is
time consuming, and frequent scanning may interfere with the normal work of the system and disks.
When lvmetad is not used, LVM commands revert to scanning disks to read metadata. Any LVM command that needs
metadata will scan disks for it; running the pvscan command is not necessary for the sake of other LVM com‐
mands.
When lvmetad is used, LVM commands avoid scanning disks by reading metadata from lvmetad. When new disks
appear, they must be scanned so their metadata can be cached in lvmetad. This is done by the command pvscan
--cache, which scans disks and passes the metadata to lvmetad.
The pvscan --cache command is typically run automatically by system services when a new device appears. Users
do not generally need to run this command if the system and lvmetad are running properly.
Many scripts contain unnecessary pvscan (or vgscan) commands for historical reasons. To avoid disrupting the
system with extraneous disk scanning, an ordinary pvscan (without --cache) will simply read metadata from
lvmetad like other LVM commands. It does not do anything beyond displaying the current state of the cache.
Notes
· When given specific device name arguments, pvscan --cache will only read the named devices.
· LVM udev rules and systemd services are used to initiate automatic device scanning.
· To prevent devices from being scanned by pvscan --cache, add them to lvm.conf(5) devices/global_filter. The
devices/filter setting does not apply to system level scanning. For more information, see:
lvmconfig --withcomments devices/global_filter
· If lvmetad is started or restarted after devices are visible, or if the global_filter has changed, then all
devices must be rescanned for metadata with the command pvscan --cache.
Auto-activation of VGs or LVs can be enabled/disabled using:
lvm.conf(5) activation/auto_activation_volume_list
For more information, see:
lvmconfig --withcomments activation/auto_activation_volume_list
When this setting is undefined, all LVs are auto-activated (when lvm is fully integrated with the event-driven
system services.)
When a VG or LV is not auto-activated, traditional activation using vgchange or lvchange -a|--activate is
needed.
Notes
· pvscan auto-activation can be only done in combination with --cache.
· Auto-activation is designated by the "a" argument in '-a|--activate ay'. This is meant to distinguish sys‐
tem generated commands from explicit user commands, although it can be used in any activation command.
Whenever it is used, the auto_activation_volume_list is applied.
· Auto-activation is not yet supported for LVs that are part of partial or clustered volume groups.
OPTIONS
See lvm(8) for common options.
-e, --exported
Only show physical volumes belonging to exported volume groups.
-n, --novolumegroup
Only show physical volumes not belonging to any volume group.
-s, --short
Short listing format.
-u, --uuid
Show UUIDs in addition to device names.
-a, --activate ay
Automatically activate any logical volumes that are possible to activate with the addition of the new
devices.
-b, --background
Run the command in the background.
--cache [--major major --minor minor | DevicePath | major:minor ]...
Scan one or more devices and send the metadata to lvmetad.
SEE ALSO
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