vgcreate(1M) vgcreate(1M)
NAME [Toc] [Back]
vgcreate - create LVM volume group
SYNOPSIS [Toc] [Back]
/usr/sbin/vgcreate [-f] [-A autobackup] [-x extensibility] [-e max_pe]
[-l max_lv] [-p max_pv] [-s pe_size] [-g pvg_name] vg_name
pv_path ...
DESCRIPTION [Toc] [Back]
The vgcreate command creates a new volume group. vg_name is a
symbolic name for the volume group and must be used in all references
to it. vg_name is the path to a directory entry under /dev that must
contain a character special file named group. Except for the group
entry, the vg_name directory should be empty. The vg_name directory
and the group file have to be created by the user (see lvm(7)).
vgcreate leaves the volume group in an active state.
Before assigning a physical volume to a volume group, the physical
volume has to be created using the pvcreate command (see
pvcreate(1M)).
If vgcreate fails to install the first specified physical volume into
the volume group, the volume group is not created. If, for any
reason, one of the remaining specified physical volumes cannot be
installed into the volume group, an error message is printed, but the
installation continues until the end of the list of physical volumes.
Options and Arguments [Toc] [Back]
vgcreate recognizes the following options and arguments:
pv_path The block device path name of a physical
volume that will be assigned to the new
volume group. On PA-RISC systems, pv_path
should be the path name for the whole disk.
For Itanium(R)-based system boot physical
volumes, pv_path should be the path name for
the disk section containing the HP-UX
partition. For Itanium-based system non-boot
physical volumes, pv_path can be the path
name for the whole disk or the disk section
containing the HP-UX partition. You can
specify physical volume links pv-links for a
physical volume providing different paths
that reference the same physical volume in
the pv_path list. The order in which the
paths are listed is important. The first
path becomes the primary link to the physical
volume, and the second becomes an alternate
link to the physical volume. The primary
link is the default path used to access the
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vgcreate(1M) vgcreate(1M)
physical volume. If the primary link becomes
unavailable, LVM automatically switches to
the alternate link to access the physical
volume. Currently, LVM supports a maximum of
8 paths to a physical volume (7 alternate and
one primary).
vg_name The path name of a subdirectory of the /dev
directory. vg_name must be empty except for
a character special file named group.
Typically, this directory name is in the form
/dev/vgNN, where NN numbers sequentially from
00.
-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 volume group.
This is the default.
After this command executes, the
vgcfgbackup command (see
vgcfgbackup(1M)) is executed for
the volume group.
n Do not back up configuration
changes this time.
-e max_pe Set the maximum number of physical extents
that can be allocated from any of the
physical volumes in the volume group. The
default value for max_pe is 1016. However,
if the size of any physical volume exceeds
1016 times the pe_size, the default value for
max_pe is adjusted to match the physical
volume size. The maximum number of physical
extents can be a value in the range 1 to
65535.
-f This option will force a volume group to be
created with a physical volume which has
alternate block(s) already allocated, (i.e.
this physical volume was not initialized
using pvcreate -f.) This option should be
used with extreme caution. If the volume
group to be created has a different physical
extent size, the alternate block(s) might be
inside the user data area. Potential data
corruption could occur.
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vgcreate(1M) vgcreate(1M)
-g pvg_name Create a new physical volume group with the
name pvg_name. All physical volumes
specified in the pv_path parameter become a
member of the newly created physical volume
group.
The physical volume group information is
stored in an ASCII file, /etc/lvmpvg. The
file can be edited to create a physical
volume group instead of using the vgcreate
command. However, ensure that the physical
volumes to be used have already been
installed in the volume group prior to
creating the physical volume group.
The physical volume group name must be unique
within a volume group although identical
physical volume group names can appear in
different volume groups (see lvmpvg(4) for
format details).
-l max_lv Set the maximum number of logical volumes
that the volume group is allowed to contain.
The default value for max_lv is 255. The
maximum number of logical volumes can be a
value in the range 1 to 255.
-p max_pv Set the maximum number of physical volumes
that the volume group is allowed to contain.
The default value for max_pv is 16. The
maximum number of physical volumes can be a
value in the range 1 to 255.
-s pe_size Sets the number of megabytes in each physical
extent, where pe_size is expressed in units
of megabytes (MB) in the range 1 to 256.
pe_size must be equal to a power of 2 (1, 2,
4, 8, etc.). The default value for pe_size
is 4 (four megabytes).
-x extensibility Set the allocation permission for adding
physical extents on the physical volumes
specified by the pv_path parameter.
extensibility can have one of the following
values:
y Allow allocation of additional
physical extents on the physical
volume. This is the default.
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n Prohibit allocation of additional
physical extents on the physical
volume. Logical volumes residing
on the physical volume can still be
accessed after the volume group has
been activated by the vgchange -a y
command.
EXTERNAL INFLUENCES [Toc] [Back]
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 [Toc] [Back]
Create a volume group named /dev/vg00 containing two physical volumes
with extent size set to 2 MB, from scratch.
First, create the directory /dev/vg00 with the character special
file called group.
mkdir /dev/vg00
mknod /dev/vg00/group c 64 0x030000
The minor number for the group file should be unique among all
the volume groups on the system. It has the format 0xNN0000,
where NN runs from 00 to ff. The maximum value of NN is
controlled by the kernel tunable parameter maxvgs.
Initialize the disks using pvcreate(1M).
pvcreate /dev/rdsk/c1t0d0
pvcreate /dev/rdsk/c1t2d0
Create the volume group.
vgcreate -s 2 /dev/vg00 /dev/dsk/c1t0d0 /dev/dsk/c1t2d0
Create a volume group named /dev/vg01 that can contain a maximum
of three logical volumes, with extent size set to 8 MB:
vgcreate -l 3 -s 8 /dev/vg01 /dev/dsk/c3t4d0
Create a volume group named /dev/vg00 and a physical volume group
named PVG0 with two physical volumes:
vgcreate -g PVG0 /dev/vg00 /dev/dsk/c1t0d0 /dev/dsk/c2t0d0
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vgcreate(1M) vgcreate(1M)
Using the PVLinks feature to create a volume group named
/dev/vg00 with a physical volume that can be referenced by two
different paths. /dev/dsk/c3t0d0 and /dev/dsk/c4t0d0 refer to
the same physical volume, accessed via different controller
hardware paths. In this example, /dev/dsk/c3t0d0 becomes the
primary link to the physical volume. /dev/dsk/c4t0d0 becomes an
alternate link to the physical volume.
vgcreate /dev/vg00 /dev/dsk/c3t0d0 /dev/dsk/c4t0d0
SEE ALSO [Toc] [Back]
idisk(1M), pvcreate(1M), vgchange(1M), vgdisplay(1M), vgextend(1M),
vgreduce(1M), lvm(7).
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