.TH VGCHANGE 8 "LVM TOOLS #VERSION#" "Sistina Software UK" \" -*- nroff -*-
.SH NAME
vgchange \- change attributes of a volume group
.SH SYNOPSIS
.B vgchange
.RB [ \-\-addtag
.IR Tag ]
.RB [ \-\-alloc
.IR AllocationPolicy ]
.RB [ \-A | \-\-autobackup " {" y | n }]
.RB [ \-a | \-\-available " [e|l] {" y | n }]
.RB [ \-\-monitor " {" y | n }]
.RB [ \-c | \-\-clustered " {" y | n }]
.RB [ \-u | \-\-uuid ]
.RB [ \-d | \-\-debug]
.RB [ \-\-deltag
.IR Tag ]
.RB [ \-h | \-\-help]
.RB [ \-\-ignorelockingfailure]
.RB [ \-\-ignoremonitoring]
.RB [ \-\-noudevsync ]
.RB [ \-l | \-\-logicalvolume
.IR MaxLogicalVolumes ]
.RB [ -p | \-\-maxphysicalvolumes
.IR MaxPhysicalVolumes ]
.RB [ \-P | \-\-partial]
.RB [ \-s | \-\-physicalextentsize
.IR PhysicalExtentSize [ \fBbBsSkKmMgGtTpPeE\fR ]]
.RB [ \-\-refresh]
.RB [ -t | \-\-test]
.RB [ \-v | \-\-verbose]
.RB [ \-\-version ]
.RB [ \-x | \-\-resizeable " {" y | n }]
.RI [ VolumeGroupName ...]
.SH DESCRIPTION
.B vgchange
allows you to change the attributes of one or more volume groups.
Its main purpose is to activate and deactivate
.IR VolumeGroupName ,
or all volume groups if none is specified.  Only active volume groups
are subject to changes and allow access to their logical volumes.
[Not yet implemented: During volume group activation, if
.B vgchange
recognizes snapshot logical volumes which were dropped because they ran
out of space, it displays a message informing the administrator that such
snapshots should be removed (see
.BR lvremove (8)).
]
.SH OPTIONS
See \fBlvm\fP for common options.
.TP
.BR \-A ", " \-\-autobackup " " { y | n }
Controls automatic backup of metadata after the change.  See
.B vgcfgbackup (8).
Default is yes.
.TP
.BR \-a ", " \-\-available " " [e|l] { y | n }
Controls the availability of the logical volumes in the volume 
group for input/output.
In other words, makes the logical volumes known/unknown to the kernel.
.IP
If clustered locking is enabled, add 'e' to activate/deactivate
exclusively on one node or 'l' to activate/deactivate only
on the local node.  
Logical volumes with single-host snapshots are always activated
exclusively because they can only be used on one node at once.
.TP
.BR \-c ", " \-\-clustered " " { y | n }
If clustered locking is enabled, this indicates whether this
Volume Group is shared with other nodes in the cluster or whether
it contains only local disks that are not visible on the other nodes.
If the cluster infrastructure is unavailable on a particular node at a
particular time, you may still be able to use Volume Groups that
are not marked as clustered.
.TP
.BR \-u ", " \-\-uuid
Generate new random UUID for specified Volume Groups.
.TP
.BR \-\-monitor " " { y | n }
Controls whether or not a mirrored logical volume is monitored by
dmeventd, if it is installed.
If a device used by a monitored mirror reports an I/O error,
the failure is handled according to 
.BR mirror_image_fault_policy
and 
.BR mirror_log_fault_policy
set in 
.BR lvm.conf (5).
.TP
.BR \-\-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
.BR \-\-ignoremonitoring
Make no attempt to interact with dmeventd unless 
.BR \-\-monitor
is specified.
Do not use this if dmeventd is already monitoring a device.
.TP
.BR \-l ", " \-\-logicalvolume " " \fIMaxLogicalVolumes\fR
Changes the maximum logical volume number of an existing inactive
volume group.
.TP
.BR \-p ", " \-\-maxphysicalvolumes " " \fIMaxPhysicalVolumes\fR
Changes the maximum number of physical volumes that can belong
to this volume group.
For volume groups with metadata in lvm1 format, the limit is 255.
If the metadata uses lvm2 format, the value 0
removes this restriction: there is then no limit.
If you have a large number of physical volumes in
a volume group with metadata in lvm2 format,
for tool performance reasons, you should consider
some use of \fB--pvmetadatacopies 0\fP
as described in \fBpvcreate(8)\fP.
.TP
.BR \-s ", " \-\-physicalextentsize " " \fIPhysicalExtentSize\fR[\fBbBsSkKmMgGtTpPeE\fR]
Changes the physical extent size on physical volumes of this volume group.
A size suffix (k for kilobytes up to t for terabytes) is optional, megabytes
is the default if no suffix is present.
The default is 4 MB and it must be at least 1 KB and a power of 2.
 
Before increasing the physical extent size, you might need to use lvresize,
pvresize and/or pvmove so that everything fits.  For example, every
contiguous range of extents used in a logical volume must start and 
end on an extent boundary.
 
If the volume group metadata uses lvm1 format, extents can vary in size from
8KB to 16GB and there is a limit of 65534 extents in each logical volume.  The
default of 4 MB leads to a maximum logical volume size of around 256GB.
 
If the volume group metadata uses lvm2 format those restrictions do not apply,
but having a large number of extents will slow down the tools but have no
impact on I/O performance to the logical volume.  The smallest PE is 1KB.
 
The 2.4 kernel has a limitation of 2TB per block device.
.TP
.BR \-\-refresh
If any logical volume in the volume group 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 \-x ", " \-\-resizeable " " { y | n }
Enables or disables the extension/reduction of this volume group
with/by physical volumes.
.SH EXAMPLES
To activate all known volume groups in the system:
.nf

\	vgchange -a y

.fi
To change the maximum number of logical volumes of inactive volume group
.B vg00
to 128.
.nf

\	vgchange -l 128 /dev/vg00

.fi
.SH SEE ALSO
.BR lvchange (8),
.BR lvm (8),
.BR vgcreate (8)
