man: expand lvchange --discard entry

[lvm2.git] / man / lvchange.8.in

.TH LVCHANGE 8 "LVM TOOLS #VERSION#" "Sistina Software UK" \" -*- nroff -*-
.SH NAME
lvchange \- change attributes of a logical volume
.SH SYNOPSIS
.B lvchange
.RB [ \-\-addtag
.IR Tag ]
.RB [ \-A | \-\-autobackup
.RI { y | n }]
.RB [ \-a | \-\-activate
.RI [ a | e | l ]{ y | n }]
.RB [ \-\-alloc
.IR AllocationPolicy ]
.RB [ \-C | \-\-contiguous
.RI { y | n }]
.RB [ \-d | \-\-debug ]
.RB [ \-\-deltag
.IR Tag ]
.RB [ \-\-discard
.RI { ignore | nopassdown | passdown }]
.RB [ \-\-resync ]
.RB [ \-h | \-? | \-\-help ]
.RB [ \-\-ignorelockingfailure ]
.RB [ \-\-ignoremonitoring ]
.RB [ \-\-monitor
.RI { y | n }]
.RB [ \-\-poll
.RI { y | n }]
.RB [ \-\-sysinit ]
.RB [ \-\-noudevsync ]
.RB [ \-M | \-\-persistent
.RI { y | n }]
.RB [ \-\-minor
.IR minor ]
.RB [ \-P | \-\-partial ]
.RB [ \-p | \-\-permission
.RI { r | rw }]
.RB [ \-r | \-\-readahead
.RI { ReadAheadSectors | auto | none }]
.RB [ \-\-refresh ]
.RB [ \-t | \-\-test ]
.RB [ \-v | \-\-verbose ]
.RB [ \-Z | \-\-zero
.RI { y | n }]
.I LogicalVolumePath
.RI [ LogicalVolumePath ...]
.SH DESCRIPTION
lvchange allows you to change the attributes of a logical volume
including making them known to the kernel ready for use.
.SH OPTIONS
See \fBlvm\fP(8) for common options.
.TP
.BR \-a ", " \-\-activate " [" \fIa | \fIe | \fIl ]{ \fIy | \fIn }
Controls the availability of the logical volumes for use.
Communicates with the kernel device-mapper driver via
libdevmapper to activate (\-ay) or deactivate (\-an) the
logical volumes. If autoactivation option is used (\-aay),
the logical volume is activated only if it matches an item in
the activation/auto_activation_volume_list set in lvm.conf.
Autoactivation is not yet supported for logical volumes that
are part of partial or clustered volume groups.
.IP
If clustered locking is enabled, -aey will activate exclusively
on one node and -aly will activate only on the local node.
To deactivate only on the local node use -aln.
Logical volumes with single-host snapshots are always activated
exclusively because they can only be used on one node at once.
.TP
.BR \-C ", " \-\-contiguous " {" \fIy | \fIn }
Tries to set or reset the contiguous allocation policy for
logical volumes. It's only possible to change a non-contiguous
logical volume's allocation policy to contiguous, if all of the
allocated physical extents are already contiguous.
.TP
.BR \-\-discard " {" \fIignore | \fInopassdown | \fIpassdown }
Set this to \fIignore\fP to ignore any discards received by a
thin pool Logical Volume.  Set to \fInopassdown\fP to process such
discards within the thin pool itself and allow the no-longer-needed
extents to be overwritten by new data.  Set to \fIpassdown\fP to
process them both within the thin pool itself and to pass them down
the underlying device.
.TP
.B \-\-resync
Forces the complete resynchronization of a mirror.  In normal
circumstances you should not need this option because synchronization
happens automatically.  Data is read from the primary mirror device
and copied to the others, so this can take a considerable amount of
time - and during this time you are without a complete redundant copy
of your data.
.TP
.B \-\-minor \fIminor
Set the minor number.
.TP
.BR \-\-monitor " {" \fIy | \fIn }
Start or stop monitoring a mirrored or snapshot logical volume with
dmeventd, if it is installed.
If a device used by a monitored mirror reports an I/O error,
the failure is handled according to
\fBmirror_image_fault_policy\fP and \fBmirror_log_fault_policy\fP
set in \fBlvm.conf\fP.
.TP
.BR \-\-poll " {" \fIy | \fIn }
Without polling a logical volume's backgrounded transformation process
will never complete.  If there is an incomplete pvmove or lvconvert (for
example, on rebooting after a crash), use \fB\-\-poll y\fP to restart the
process from its last checkpoint.  However, it may not be appropriate to
immediately poll a logical volume when it is activated, use
\fB\-\-poll n\fP to defer and then \fB\-\-poll y\fP to restart the process.
.TP
.B \-\-sysinit
Indicates that \fBlvchange\fP(8) is being invoked from early system
initialisation scripts (e.g. rc.sysinit or an initrd),
before writeable filesystems are available. As such,
some functionality needs to be disabled and this option
acts as a shortcut which selects an appropriate set of options. Currently
this is equivalent to using  \fB\-\-ignorelockingfailure\fP,
\fB\-\-ignoremonitoring\fP, \fB\-\-poll n\fP and setting
\fBLVM_SUPPRESS_LOCKING_FAILURE_MESSAGES\fP
environment variable.

If \fB\-\-sysinit\fP is used in conjunction with lvmetad(8) enabled and running,
autoactivation is preferred over manual activation via direct lvchange call.
Logical volumes are autoactivated according to auto_activation_volume_list
set in lvm.conf(5).
.TP
.B \-\-noudevsync
Disable udev synchronisation. The
process will not wait for notification from udev.
It will continue irrespective of any possible udev processing
in the background.  You should only use this if udev is not running
or has rules that ignore the devices LVM2 creates.
.TP
.B \-\-ignoremonitoring
Make no attempt to interact with dmeventd unless \fB\-\-monitor\fP
is specified.
Do not use this if dmeventd is already monitoring a device.
.TP
.BR \-M ", " \-\-persistent " {" \fIy | \fIn }
Set to y to make the minor number specified persistent.
.TP
.BR \-p ", " \-\-permission " {" \fIr | \fIrw }
Change access permission to read-only or read/write.
.TP
.BR \-r ", " \-\-readahead " {" \fIReadAheadSectors | \fIauto | \fInone }
Set read ahead sector count of this logical volume.
For volume groups with metadata in lvm1 format, this must
be a value between 2 and 120 sectors.
The default value is "auto" which allows the kernel to choose
a suitable value automatically.
"None" is equivalent to specifying zero.
.TP
.B \-\-refresh
If the logical volume is active, reload its metadata.
This is not necessary in normal operation, but may be useful
if something has gone wrong or if you're doing clustering
manually without a clustered lock manager.
.TP
.BR \-Z ", " \-\-zero " {" \fIy | \fIn }
Set zeroing mode for thin pool. Note: already provisioned blocks from pool
in non-zero mode are not cleared in unwritten parts when setting zero to
\fIy\fP.
.SH Examples
Changes the permission on volume lvol1 in volume group vg00 to be read-only:
.sp
.B lvchange -pr vg00/lvol1
.SH SEE ALSO
.BR lvm (8),
.BR lvcreate (8),
.BR vgchange (8)