lvm2/man/pvscan.8_des

When called without the --cache option, pvscan lists PVs on the system,
like
.BR pvs (8)
or
.BR pvdisplay (8).
.P
When --cache is used, pvscan updates runtime lvm state on the system, or
with -aay performs autoactivation.
.P
.B pvscan --cache
.I device
.P
If device is present, lvm records that the PV on device is online.
If device is not present, lvm removes the online record for the PV.
pvscan only reads the named device.
.P
.B pvscan --cache
.P
Updates the runtime state for all lvm devices.
.P
.B pvscan --cache -aay
.I device
.P
Performs the --cache steps for the device, then checks if the VG using the
device is complete.  If so, LVs in the VG are autoactivated, the same as
vgchange -aay vgname would do.  (A device name may be replaced with major
and minor numbers.)
.P
.B pvscan --cache -aay
.P
Performs the --cache steps for all devices, then autoactivates any complete VGs.
.P
.B pvscan --cache --listvg|--listlvs
.I device
.P
Performs the --cache steps for the device, then prints the name of the VG
using the device, or the names of LVs using the device.  --checkcomplete
is usually included to check if all PVs for the VG or LVs are online.
When this command is called by a udev rule, the output must conform to
udev rule specifications (see --udevoutput.)  The udev rule will use the
results to perform autoactivation.
.P
Autoactivation of VGs or LVs can be enabled/disabled using vgchange or
lvchange with --setautoactivation y|n, or by adding names to
.BR lvm.conf (5)
.B activation/auto_activation_volume_list
.P
See
.BR lvmautoactivation (7)
for more information about how pvscan is used for autoactivation.