pvscan(8)

NAME

   pvscan --- scan all disks for physical volumes

SYNOPSIS

   pvscan    [--commandprofile   ProfileName]   [-d|--debug]   [-h|--help]
   [-v|--verbose]  [--version]  [--ignorelockingfailure]   [-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
   commands.

   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.

   * lvmetad does not cache older metadata formats, e.g. lvm1, and will be
     temporarily disabled if they are seen.

   * To notify lvmetad about a device that is no longer present, the major
     and minor numbers must be given, not the path.

   Automatic activation
   When  event-driven  system  services detect a new LVM device, the first
   step is to automatically scan and cache the metadata from  the  device.
   This  is  done  by  pvscan  --cache.  A second step is to automatically
   activate LVs that are present on the new device.  This  auto-activation
   is   done   by   the  same  pvscan  --cache  command  when  the  option
   '-a|--activate ay' is included.

   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 system 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

   lvm(8), lvmconfig(8), lvmetad(8)

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