pvchange — change characteristics and access path of physical volume in LVM volume group
can be performed if the volume group is activated in shared mode.
All other options are not allowed for physical volumes in shared volume groups.
command changes the characteristics and access path of a physical volume
in a volume group.
For multiported devices accessed via multiple paths,
may be used to customize the circumstances that may cause LVM to
automatically switch from one path to another, or when LVM will switch
back to a prior path which failed when it is available again
(generally described as the physical volume's
also permits you to switch manually to a specific
path to the physical volume
sets the allocation permission to add physical extents to the physical volume.
If you have installed the optional HP MirrorDisk/UX software, you
can use the
option to designate a spare physical volume to be used to replace
an existing physical volume within a volume group when mirroring
is in effect, in the event the
existing physical volume fails.
can also be used to
specific paths or physical volumes
Options and Arguments
recognizes the following options and arguments.
The block device path name of a physical volume.
- -A autobackup
Set automatic backup for this invocation of this command.
can have one of the following values:
Automatically back up configuration changes made to the logical volume.
This is the default.
After this command executes, the
is executed for the volume group to which the logical volume belongs.
Do not back up configuration changes this time.
- -a availability
Attach or detach the physical volume
can have the following values:
Attach the indicated path to the physical volume.
path or device is available for LVM to use.
Attaching a path makes that path available to the volume group, if possible.
LVM may begin using the path if necessary to access the disk.
If formerly all the paths were unavailable to a given physical volume,
making any path available will make the physical volume available again.
the indicated path to the physical volume.
path is not available for LVM to use.
Detaching a single path causes LVM to close the device for that one path
and to stop using it.
If the path is the primary path to the device,
LVM will begin using the best alternate path to the device that is available.
When the only path to a device is detached, the associated physical volume
will be unavailable to the volume group.
The path remains part of the volume group but no I/O is queued to
it and the path will remain unused by LVM until it is reattached.
LVM will only stop using the physical volume when
the paths to the physical volume are detached.
Individually detaching all the paths to a physical volume has
the same consequences as detaching the physical volume entirely using the
The system administrator may safely diagnose or replace hardware along the
path detached, but care should be taken to avoid accessing the physical
volume if it is still being accessed by LVM via other active paths to
Detach the given path and all other paths to the physical volume.
The system administrator should always presume that all the disks
that belong to an active volume group are attached and may be
used by LVM at any time, unless LVM has been specifically notified
to detach them.
Prior to replacing or repairing any disk
belonging to an active volume group, the administrator must
first detach the physical volume using this command.
When a physical volume is detached, LVM closes all the paths to the
physical volume and no longer directs any I/O operations to it.
If a suitable spare physical volume is available in the volume group,
LVM will use it to reconstruct the detached disk. The given path must
be an attached path to the physical volume; otherwise, the command will
fail and display an error message indicating the problem.
If for any reason the use of the
option fails, the physical volume can still be detached from the volume group
by individually detaching each of the paths to the physical volume
section). Immediately begin accessing the associated physical volume
- -S autoswitch
section). This option specifies the
behavior for multiported physical volumes accessed via multiple paths.
It has no effect for physical volumes without alternate paths.
option may be set to one of the following values:
LVM is directed to automatically switch from the path it is using whenever a
better path to the physical volume is available.
LVM will switch paths when a better path recovers (after it had
failed earlier), or if the current path fails and another path is available.
This is the default.
LVM is directed to automatically switch to using the best available path only
when the path currently in use is unavailable.
LVM will continue using a specific path for the physical volume
as long as it works, regardless of whether another better path
recovers from a failure.
- -x extensibility
Set the allocation permission to add physical extents to the physical volume
can have the following values:
Allow allocation of additional physical extents on the physical volume.
This is the default.
Prohibit allocation of additional physical extents on the physical volume.
However, logical volumes residing on the physical volume are accessible.
- -t IO_timeout
Set the I/O timeout value for the physical volume, to the number of
seconds indicated. An I/O timeout value of zero (0) causes the system
to use the default value supplied by the device driver associated with
the physical device. I/O timeout value is used by the device driver to
determine how long to wait for disk transactions to complete before
concluding that an I/O request can not be completed (and the device is
offline or unavailable).
- -z sparepv
This option requires the installation of the optional HP MirrorDisk/UX
software. It allows you to change the physical volume specified by
into a spare physical volume for its
volume group, or change the specified spare physical volume back into a regular
physical volume for this volume group. No physical extents from
a spare physical volume will be available as part of the "free" pool of
extents in the volume group. A spare physical volume will only be used
in the event that another physical volume within this volume group
becomes unavailable (fails).
can have one of the following values:
Change the specified physical volume to be a "stand-by" spare for its
volume group. The specified physical volume must not have extents
allocated on it (i.e., no logical
volumes residing on it) at the time this command is
issued. A stand-by spare physical volume will only be
used in the event of a failure of another physical volume -- prior
to such a failure, no
logical volume is allowed to reside on it.
Change the specified spare physical volume back into a regular physical volume.
If the physical volume was a stand-by spare, then all of the
disk space associated with it will be immediately available for use by
logical volumes. If the physical volume is an "active" spare, that is,
it was previously a stand-by spare but then took over for a
failed physical volume, it will
simply mark the physical volume as a regular member of its volume group
and the logical volumes residing on it will remain unchanged.
Attaching and Detaching Physical Volumes
Detaching a physical volume makes the data on that disk unavailable.
LVM will not write or read any user data or LVM metadata to the disk
while it is detached. Consequently, it is important for the
administrator to ensure that the data on the disk is sufficiently
mirrored to satisfy availability requirements prior to making
the device unavailable by detaching it.
Although detaching a path or physical volume ensures it is unavailable
to LVM, attaching a path or physical volume will not necessarily make
the path or physical volume available again. Attaching a path or
physical volume only makes it available for LVM to use once the
disk is working. For instance, if a disk is spinning up, LVM
will successfully attach the disk, but the disk will not be available
until it is ready.
Detaching a physical volume or path only temporarily changes the status
of the indicated path or physical volume. However, it does not change the
volume group configuration. When a physical volume is detached, it will
automatically be attached again the next time the volume group is activated
If the objective is to permanently add or remove a path or physical
volume from the volume group, the
should instead be used.
Detaching any physical volume or path using the
options also disables automatically attaching
paths to any of the physical volumes in the volume group.
LVM will no longer attempt to automatically recover any unattached
physical volumes in the volume group, not just the ones explicitly detached.
To cause LVM to once again automatically attach devices in the volume group
Attaching or Detaching Physical Volumes in Shared Volume Groups
The scope of the
command is limited to the specific node on
which it runs. Systems that are part of a Serviceguard cluster operate
independently. To replace disks that are part of a volume group shared
by a Serviceguard cluster, the physical volume must be detached and
attached independently on each of the systems in the cluster.
Alternate Links (PVLINKS)
In this release of HP-UX, LVM continues to support Alternate Links to a
device to allow continued access to the device, if the primary link
fails. This multiple link or multipath solution increases data
availability, but does not allow the multiple paths to be used
There is a new feature introduced in the Mass Storage Subsystem on this
version of HP-UX that also supports multiple paths to a device and
allows access to the multiple paths simultaneously. The Mass Storage
Subsystem will balance the I/O load across the valid paths. This new
multi-path behavior is enabled and disabled through the use of the
It is no longer required or recommended to configure LVM with alternate
links. However, it is possible to maintain the traditional LVM
behavior. To do so, both of the following criteria must be met:
Only the legacy device special file naming convention is used in the
volume group configuration.
command is used to disable the Mass Storage Subsystem
determines the language in which messages are displayed.
is not specified or is null, it defaults to
If any internationalization variable contains an invalid setting,
all internationalization variables default to
Prohibit the allocation of additional physical extents to a physical volume:
pvchange -x n /dev/dsk/c0t0d0
Allow the allocation of additional physical extents to a physical volume:
pvchange -x y /dev/dsk/c0t0d0
Only switch paths when the current path is unavailable. Do not
switch back to a prior path which had failed and has recovered,
when the current path works:
pvchange -S n /dev/dsk/c0t0d0
Switch paths whenever a better path becomes available again after a
failure, even if the current path is fine:
pvchange -S y /dev/dsk/c0t0d0
Manually switch a physical volume to use another controller path:
pvchange -s /dev/dsk/c2t0d2
for a physical volume to 60 seconds:
pvchange -t 60 /dev/dsk/c2t0d2
for a physical volume to zero (0) to use the driver default:
pvchange -t 0 /dev/dsk/c2t0d2
Change the (empty) physical volume to become a stand-by spare for the volume
pvchange -z y /dev/dsk/c2t0d2
Change the (active or stand-by) spare physical volume to become a regular
member of the volume group:
pvchange -z n /dev/dsk/c2t0d2
Detach a path to a physical volume
pvchange -a n /dev/dsk/c2t0d2
Detach all the paths to a physical volume
pvchange -a N /dev/dsk/c2t0d2
Attach a path to a physical volume
pvchange -a y /dev/dsk/c2t0d2
command may be used to attach all the physical volumes in a
volume group and resume automatically attaching the failed physical
vgchange -a y /dev/vg_work
If the Mass Storage Subsystem multipath solution is enabled, the
command options that are link specific may not stop I/Os or
switch links, as they did in earlier releases.
This means that
pvchange -a n,
may not stop all I/Os on a given path.
command should be
used to disable the links.