NAME | SYNOPSIS | DESCRIPTION | USAGE | OPTIONS | VARIABLES | ENVIRONMENT VARIABLES | SEE ALSO | COLOPHON

PVSCAN(8)                  System Manager's Manual                 PVSCAN(8)

NAME         top

       pvscan - List all physical volumes

SYNOPSIS         top

       pvscan option_args
           [ option_args ]
           [ position_args ]

DESCRIPTION         top

       pvscan scans all supported LVM block devices in the system for PVs.

       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.

       · 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.

       · 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.

USAGE         top

       Display PV information.

       pvscan
           [ -e|--exported ]
           [ -n|--novolumegroup ]
           [ -s|--short ]
           [ -u|--uuid ]
           [ COMMON_OPTIONS ]

       Populate the lvmetad cache by scanning PVs.

       pvscan --cache
           [ -b|--background ]
           [ -a|--activate ay ]
           [ -j|--major Number ]
           [    --minor Number ]
           [ COMMON_OPTIONS ]
           [ String|PV ... ]

       Common options for command:
           [    --ignorelockingfailure ]
           [    --reportformat basic|json ]

       Common options for lvm:
           [ -d|--debug ]
           [ -h|--help ]
           [ -q|--quiet ]
           [ -t|--test ]
           [ -v|--verbose ]
           [ -y|--yes ]
           [    --commandprofile String ]
           [    --config String ]
           [    --driverloaded y|n ]
           [    --longhelp ]
           [    --profile String ]
           [    --version ]

OPTIONS         top

       -a|--activate y|n|ay
              Auto-activate LVs in a VG when the PVs scanned have completed
              the VG.  (Only ay is applicable.)

       -b|--background
              If the operation requires polling, this option causes the
              command to return before the operation is complete, and
              polling is done in the background.

       --cache
              Scan one or more devices and send the metadata to lvmetad.

       --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
              settings.  The String arg uses the same format as lvm.conf, or
              may use section/field syntax.  See lvm.conf(5) for more
              information 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).

       --driverloaded y|n
              If set to no, the command will not attempt to use device-
              mapper.  For testing and debugging.

       -e|--exported
              Only show PVs belonging to exported VGs.

       -h|--help
              Display help text.

       --ignorelockingfailure
              Allows a command to continue with read-only metadata
              operations after locking failures.

       --longhelp
              Display long help text.

       -j|--major Number
              The major number of a device.

       --minor Number
              The minor number of a device.

       -n|--novolumegroup
              Only show PVs not belonging to any VG.

       --profile String
              An alias for --commandprofile or --metadataprofile, depending
              on the command.

       -q|--quiet ...
              Suppress output and log messages. Overrides --debug and
              --verbose.  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.
              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.

       -s|--short
              Short listing format.

       -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
              Show UUIDs in addition to device names.

       -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.)

VARIABLES         top

       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
              content.

       Size[UNIT]
              Size is an input number that accepts an optional unit.  Input
              units are always treated as base two values, regardless of
              capitalization, e.g. 'k' and 'K' both refer to 1024.  The
              default input unit is specified by letter, followed by |UNIT.
              UNIT represents other possible input units: bBsSkKmMgGtTpPeE.
              b|B is bytes, s|S is sectors of 512 bytes, k|K is kilobytes,
              m|M is megabytes, g|G is gigabytes, t|T is terabytes, p|P is
              petabytes, e|E is exabytes.  (This should not be confused with
              the output control --units, where capital letters mean
              multiple of 1000.)

ENVIRONMENT VARIABLES         top

       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         top

       lvm(8) lvm.conf(5) lvmconfig(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) 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) lvmetad(8) lvmpolld(8) lvmlockd(8) lvmlockctl(8) clvmd(8)
       cmirrord(8) lvmdbusd(8)

       lvmsystemid(7) lvmreport(7) lvmraid(7) lvmthin(7) lvmcache(7)

COLOPHON         top

       This page is part of the lvm2 (Logical Volume Manager 2) project.
       Information about the project can be found at 
       ⟨http://www.sourceware.org/lvm2/⟩.  If you have a bug report for this
       manual page, send it to linux-lvm@redhat.com.  This page was obtained
       from the project's upstream Git repository 
       ⟨git://sourceware.org/git/lvm2.git⟩ on 2017-09-15.  If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

Red Hat, Inc.      LVM TOOLS 2.02.175(2)-git (2017-09-13)          PVSCAN(8)

Pages that refer to this page: lvchange(8)lvconvert(8)lvcreate(8)lvdisplay(8)lvextend(8)lvm2-activation-generator(8)lvm(8)lvmconfig(8)lvmdiskscan(8)lvmetad(8)lvm-fullreport(8)lvm-lvpoll(8)lvreduce(8)lvremove(8)lvrename(8)lvresize(8)lvs(8)lvscan(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)vgconvert(8)vgcreate(8)vgdisplay(8)vgexport(8)vgextend(8)vgimport(8)vgimportclone(8)vgmerge(8)vgmknodes(8)vgreduce(8)vgremove(8)vgrename(8)vgs(8)vgscan(8)vgsplit(8)