lvchange(1M)

NAME

lvchange − change LVM logical volume characteristics

SYNOPSIS

/sbin/lvchange [-a availability] [-A autobackup] [-c mirror_consistency] [-C contiguous]
[-d schedule] [-M mirror_write_cache] [-p permission] [-r relocate] [-s strict] lv_path

Remarks

Mirror disk operations require the installation of the optional HP MirrorDisk/UX software, which is not included in the standard HP-UX operating system. lvchange cannot be performed if the volume group is activated in shared mode.

DESCRIPTION

The lvchange command changes certain characteristics of a logical volume. Other characteristics can be changed with the lvextend and lvreduce commands (see lvextend(1M) and lvreduce(1M)).

The command-line options specify the type and extent of change. Each current characteristic for a logical volume remains in effect until explicitly changed by the corresponding option. All options take effect immediately, except -s, which takes effect only when new extents are allocated by the lvextend command.

If a logical volume is striped, its scheduling policy is always parallel and its allocation policy is always strict and noncontiguous; these attributes cannot be changed with lvchange.

Options and Arguments

The -c, -d, -M, and -s options are meaningful only if the optional HP MirrorDisk/UX software has been installed on the system.

lvchange recognizes the following options and arguments:

lv_path The block device path name of a logical volume.

-a availability Set logical volume availability. availability can have one of the following values:

y Make a logical volume available. An open of the logical volume will succeed.

n Make a logical volume temporarily unavailable. An open of the logical volume will fail. However, all current processes that have the logical volume open remain open.

-A autobackup Set automatic backup for this invocation of this command. autobackup can have one of the following values:

y Automatically back up configuration changes made to the logical volume. This is the default.

After this command executes, the vgcfgbackup command (see vgcfgbackup(1M)) is executed for the volume group to which the logical volume belongs.

n Do not back up configuration changes this time.

-c mirror_consistency Set mirror consistency recovery. This option is effective only when -M n is specified or previously set. mirror_consistency can have one of the following values:

y Set mirror consistency recovery on. LVM achieves mirror consistency during volume group activation by going through all logical extents and copying data from a nonstale copy to the other mirror copies.

n Set mirror consistency recovery off. LVM does not perform mirror consistency recovery on this logical volume when the volume group is activated.

-C contiguous Set the contiguous allocation policy. contiguous can have one of the following values:

y Set a contiguous allocation policy. Physical extents are allocated in ascending order without any gap between adjacent extents and all extents are contained in a single physical volume.

n Do not set a contiguous allocation policy.

A nonempty logical volume that has a noncontiguous allocation policy cannot be changed to a contiguous allocation policy unless it happens to meet all the requirements of the contiguous allocation policy. See lvcreate(1m) for more information about the contiguous allocation policy.

-d schedule Set the scheduling policy when a logical extent with more than one mirror is written. (The scheduling policy of a striped logical volume is striped and cannot be changed.) schedule can have one of the following values:

p Establish a parallel scheduling policy.

s Establish a sequential scheduling policy. Use this value with care, because it leads to performance loss in most cases.

-M mirror_write_cache Set the Mirror Write Cache flag. This option is allowed only when the logical volume is not opened. mirror_write_cache can have one of the following values:

y Set Mirror Write Cache on. Every write to a mirror copy is recorded in the Mirror Write Cache and written into the Mirror Consistency Record on the disk if a cache-miss occurs. This allows LVM to determine whether all mirror copies are identical, even across system crashes. When the volume group is activated, the Mirror Consistency Record is used to perform mirror consistency recovery.

n Set Mirror Write Cache off. Mirror write does not incur an additional write to the Mirror Consistency Record on the disk.

-p permission Set the access permission. permission can have one of the following values:

w Set the access permission to read-write.

r Set the access permission to read-only.

-r relocate Set the bad block relocation policy. relocate can have one of the following values:

y Allow bad block relocation.

n Prevent bad block relocation.

-s strict Set the strict allocation policy. Mirror copies of a logical extent can be allocated to share or not share the same physical volume or physical volume group. This option only makes sense when the physical volumes of the volume group that owns the specified logical volume reside on different physical disks. strict can have one of the following values:

y Set a strict allocation policy. Mirrors of a logical extent cannot share the same physical volume.

g Set a PVG-strict allocation policy. Mirrors of a logical extent cannot share the same physical volume group.

n Do not set a strict or a PVG-strict allocation policy. Mirrors of a logical extent can share the same physical volume.

When a logical volume is mirrored, the following changes are not allowed:

• From nonstrict to strict

• From nonstrict to PVG-strict

• From strict to PVG-strict

EXTERNAL INFLUENCES

Environment Variables

LANG determines the language in which messages are displayed.

If LANG is not specified or is null, it defaults to "C" (see lang(5)).

If any internationalization variable contains an invalid setting, all internationalization variables default to "C" (see environ(5)).

EXAMPLES

Change the permission of a logical volume to read-only:

lvchange -p r /dev/vg01/lvol3

Change the allocation policy of a logical volume to nonstrict:

lvchange -s n /dev/vg01/lvol7

Turn the mirror write cache off on a logical volume:

lvchange -M n /dev/vg01/lvol1

DEPENDENCIES

The -r option is not available on HP-IB devices.

WARNINGS

For root, swap or dump logical volumes, its allocation policy is always contiguous. This attribute cannot be changed with lvchange.

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