PVSCAN(8) System Manager's Manual PVSCAN(8)
NAME
pvscan - List all physical volumes
SYNOPSIS
pvscan option_args
[ option_args ]
[ position_args ]
DESCRIPTION
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 his-
torical reasons. To avoid disrupting the system with extraneous disk
scanning, an ordinary pvscan (without --cache) will simply read meta-
data from lvmetad like other LVM commands. It does not do anything
beyond displaying the current state of the cache.
o When given specific device name arguments, pvscan --cache will only
read the named devices.
o LVM udev rules and systemd services are used to initiate automatic
device scanning.
o 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
o 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.
o lvmetad does not cache older metadata formats, e.g. lvm1, and will be
temporarily disabled if they are seen.
o 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 --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 --activate is needed.
o pvscan auto-activation can be only done in combination with --cache.
o Auto-activation is designated by the "a" argument in --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.
o Auto-activation is not yet supported for LVs that are part of partial
or clustered volume groups.
USAGE
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 ]
[ --lockopt String ]
[ --longhelp ]
[ --profile String ]
[ --version ]
OPTIONS
-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 com-
mand 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 set-
tings. 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.
--lockopt String
Used to pass options for special cases to lvmlockd. See lvm-
lockd(8) for more information.
--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 --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. 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
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: 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
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)
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) vgcon-
vert(8) vgdisplay(8) vgexport(8) vgextend(8) vgimport(8) vgimport-
clone(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) lvre-
duce(8) lvremove(8) lvrename(8) lvresize(8) lvs(8) lvscan(8)
lvm-fullreport(8) lvm-lvpoll(8) lvm2-activation-generator(8) blkdeacti-
vate(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)
Red Hat, Inc. LVM TOOLS 2.02.187(2)-RHEL7 (2020-03-24) PVSCAN(8)
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