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authorZdenek Kabelac <zkabelac@redhat.com>2018-11-29 23:08:25 +0100
committerZdenek Kabelac <zkabelac@redhat.com>2018-11-29 23:10:08 +0100
commite3a22cdc31c38939efd51dd9a3a82e034adc21c5 (patch)
tree58dba0ea0de79fd36e34b839c64e70a860b61cbf /man/pvscan.8_pregen
parentfc482406ec4e0607a9d7335ac927c64b361cad1c (diff)
downloadlvm2-e3a22cdc31c38939efd51dd9a3a82e034adc21c5.tar.gz
make: generate man update
Diffstat (limited to 'man/pvscan.8_pregen')
-rw-r--r--man/pvscan.8_pregen111
1 files changed, 35 insertions, 76 deletions
diff --git a/man/pvscan.8_pregen b/man/pvscan.8_pregen
index 2326ec55e..ed5ba9241 100644
--- a/man/pvscan.8_pregen
+++ b/man/pvscan.8_pregen
@@ -10,73 +10,50 @@ pvscan - List all physical volumes
[ \fIposition_args\fP ]
.br
.SH DESCRIPTION
-pvscan scans all supported LVM block devices in the system for PVs.
+When called without the --cache option, pvscan lists PVs on the system,
+like
+.BR pvs (8)
+or
+.BR pvdisplay (8).
+
+When the --cache and -aay options are used, pvscan records which PVs are
+available on the system, and activates LVs in completed VGs. A VG is
+complete when pvscan sees that the final PV in the VG has appeared. This
+is used by event-based system startup (systemd, udev) to activate LVs.
+
+The four main variations of this are:
+
+.B pvscan --cache
+.IR device
-\fBScanning with lvmetad\fP
+If device is present, lvm adds a record that the PV on device is online.
+If device is not present, lvm removes the online record for the PV.
+In most cases, the pvscan will only read the named devices.
-pvscan operates differently when used with the
-.BR lvmetad (8)
-daemon.
+.B pvscan --cache -aay
+.IR device ...
-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.
+This begins by performing the same steps as above. Afterward, if the VG
+for the specified PV is complete, then pvscan will activate LVs in the VG
+(the same as vgchange -aay vgname would do.)
-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.
+.B pvscan --cache
-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.
+This first clears all existing PV online records, then scans all devices
+on the system, adding PV online records for any PVs that are found.
-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.
+.B pvscan --cache -aay
+
+This begins by performing the same steps as pvscan --cache. Afterward, it
+activates LVs in any complete VGs.
-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.
-.IP \[bu] 2
-When given specific device name arguments, pvscan --cache will only
-read the named devices.
-.IP \[bu] 2
-LVM udev rules and systemd services are used to initiate automatic device
-scanning.
-.IP \[bu] 2
To prevent devices from being scanned by pvscan --cache, add them
to
.BR lvm.conf (5)
.B devices/global_filter.
-The devices/filter setting does not
-apply to system level scanning.
For more information, see:
.br
.B lvmconfig --withcomments devices/global_filter
-.IP \[bu] 2
-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.
-.IP \[bu] 2
-lvmetad does not cache older metadata formats, e.g. lvm1, and will
-be temporarily disabled if they are seen.
-.IP \[bu] 2
-To notify lvmetad about a device that is no longer present, the major and
-minor numbers must be given, not the path.
-.P
-\fBAutomatic activation\fP
-
-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:
.br
@@ -87,21 +64,12 @@ For more information, see:
.br
.B 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.)
+To disable auto-activation, explicitly set this list to an empty list,
+i.e. auto_activation_volume_list = [ ].
+
+When this setting is undefined (e.g. commented), then all LVs are
+auto-activated.
-When a VG or LV is not auto-activated, traditional activation using
-vgchange or lvchange --activate is needed.
-.IP \[bu] 2
-pvscan auto-activation can be only done in combination with --cache.
-.IP \[bu] 2
-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.
-.IP \[bu] 2
-Auto-activation is not yet supported for LVs that are part of partial or
-clustered volume groups.
.SH USAGE
Display PV information.
.br
@@ -136,10 +104,6 @@ Autoactivate a VG when all PVs are online.
.br
.RS 4
.ad l
-[ \fB-b\fP|\fB--background\fP ]
-.ad b
-.br
-.ad l
[ \fB-a\fP|\fB--activate\fP \fBay\fP ]
.ad b
.br
@@ -239,9 +203,6 @@ Auto-activate LVs in a VG when the PVs scanned have completed the VG.
.ad b
.HP
.ad l
-\fB-b\fP|\fB--background\fP.ad b
-.HP
-.ad l
\fB--cache\fP
.br
Scan one or more devices and record that they are online.
@@ -486,11 +447,9 @@ For example, LVM_VG_NAME can generally be substituted for a required VG paramete
.BR lvmdump (8)
.BR dmeventd (8)
-.BR lvmetad (8)
.BR lvmpolld (8)
.BR lvmlockd (8)
.BR lvmlockctl (8)
-.BR clvmd (8)
.BR cmirrord (8)
.BR lvmdbusd (8)