vgcreate(1M) vgcreate(1M)
NAME
vgcreate - create LVM volume group
SYNOPSIS
autobackup] extensibility] max_pe] max_lv] max_pv] pe_size] pvg_name] vg_name pv_path ...
pe_size vg_size autobackup] extensibility] pvg_name] vg_name pv_path ...
pe_size | vg_size}
DESCRIPTION
The command without the option creates a new volume group. vg_name is a symbolic name for the volume group and must be used in all refer-
ences to it. vg_name is the path to a directory entry under that must contain a character special file named Except for the entry, the
vg_name directory should be empty. A user may explicitly create the vg_name directory and the file before creating the volume group. If
absent, the command will automatically create the directory and the file, assigning the minor number. If the file is automatically cre-
ated, any available minor number may be assigned to the file.
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 command (see pvcreate(1M)).
If 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 con-
tinues until the end of the list of physical volumes.
The command with the option displays information which may be useful in deciding on parameters for use in creating a volume group version
2.0 and higher.
The option (only for volume groups versions 2.0 and higher) displays the relationship between physical extent size (pe_size) and maximum
volume group size (vg_size). See lvm(7) for more on this topic. A pe_size or a vg_size must be supplied on the command line. If pe_size
is specified, then the maximum volume group size which can be created using that extent size is displayed using the suffix notation
explained in the description of the option. If the vg_size is specified then the minimum extent size required to support the given maximum
volume group size is displayed in megabytes.
Options and Arguments
recognizes the following options and arguments:
Specify the version of the volume group.
Currently only and are supported. Different versions represent significant changes in LVM software and data
layout and may have compatibility implications when volume groups are shared or moved from system to system.
See lvm(7) for more details. The default version is 1.0.
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 HP Integrity system boot physical
volumes, pv_path should be the path name for the disk section containing the HP-UX partition (see model(1) and
getconf(1)). For HP Integrity 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 to the physical volume, and the second becomes an to the physical volume. The is the default
path used to access the physical volume. (see section). If the becomes unavailable, LVM automatically switches
to the 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 directory. vg_name must be empty except for a character special file
named Typically, this directory name is in the form where NN numbers sequentially from
Set automatic backup for this invocation of this command.
autobackup can have one of the following values:
Automatically back up configuration changes made to the volume group.
This is the default.
After this command executes, the command (see vgcfgbackup(1M)) is executed for the volume group.
Do not back up configuration changes this time.
Only applicable to volume groups version 1.0.
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 However, if the size of any physical volume exceeds 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.
Only applicable to volume groups version 1.0.
This option will force a volume group to be created with a physical volume which has alternate block(s) already
allocated, (that is, this physical volume was not initialized using This option should be used with extreme cau-
tion. 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.
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, The file can be edited to create a physical
volume group instead of using the 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).
Only applicable to volume groups version 1.0.
Set the maximum number of logical volumes that the volume group is allowed to contain. The default value for
max_lv is The maximum number of logical volumes can be a value in the range 1 to 255.
Only applicable to volume groups version 1.0.
Set the maximum number of physical volumes that the volume group is allowed to contain. The default value for
max_pv is The maximum number of physical volumes can be a value in the range 1 to 255.
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 (four megabytes) for volume groups version 1.0. For vol-
ume groups versions 2.0 and higher, this is a required parameter. See lvm(7) for more information on extent
sizes on volume groups versions 2.0 and higher.
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:
Allow allocation of additional physical extents on the physical volume.
This is the default.
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 command.
Only applicable to volume groups versions 2.0 and 2.1.
Sets the maximum size of the volume group. The maximum size is the total size of all physical extents in the
volume group. The unit for is specified as a suffix. The recognized values for the suffix are (megabytes),
(gigabytes), (terabytes), and (petabytes). If no suffix is supplied, then (megabytes) is assumed. A of 512
terabytes would be specified as 512t. Only whole numbers are accepted. The maximum supported vg_size is 2p.
If the product of the physical extent size and the total number of physical extents for the physical volumes
specified on the command line is greater than the value specified, then vg_size is upgraded to take account of
this size and an informational message is issued.
Only applicable to volume groups versions 2.0 and higher.
Either or must be supplied. This option will display the maximum VG size based on the given physical extent
size option) or minimum physical extent size based on the max VG size option). The output will be in where x
and y are determined by or See the section in lvm(7) for more information.
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 simultane-
ously.
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 scsimgr command. See scsimgr(1M) for details.
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:
o Only the legacy device special file naming convention is used in the volume group configuration.
o The command is used to disable the Mass Storage Subsystem multipath behavior.
EXTERNAL INFLUENCES
Environment Variables
determines the language in which messages are displayed.
If 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
Create a volume group version 1.0 named containing two physical volumes with extent size set to 2 MB, from scratch.
Initialize the disks using
Create a volume group version 1.0.
or
The vg_name directory and group file will be created automatically. Optionally, these files can be created before doing the vgcre-
ate, as follows:
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 to
If the file is automatically created, any available minor number may be assigned to the group file.
Create a volume group version 1.0 named that can contain a maximum of three logical volumes, with extent size set to 8 MB:
Create a volume group version 1.0 named and a physical volume group named with two physical volumes:
Using the feature to create a volume group version 1.0 named with a physical volume that can be referenced by two different paths.
and refer to the same physical volume, accessed via different controller hardware paths. In this example, becomes the to the physi-
cal volume. becomes an to the physical volume.
Create a volume group version 2.0 named with 2 physical volumes, an extent size of 256 megabytes and a maximum total size of 1 petabyte.
Initialize the disks using pvcreate
Create the volume group version 2.0.
The directory and file will be created automatically. Optionally, these files can be created before doing the as follows:
Notice that the major number for a volume group version 2.0 or higher is 128 while the major number for a volume group version 1.0
is 64. Also, the volume group number occupies the high order 12 bits of the minor number rather than the high order 8 bits as in
volume groups version 1.0.
Create a volume group version 2.0 of size comparable to a volume group version 1.0 created with and on an already initialized disk.
First calculate the appropriate vg_size parameter as follows: (in megabytes) Now create the volume group version 2.0.
Display the minimum extent size required to create a 512 terabyte volume group version 2.0.
SEE ALSO
getconf(1), model(1), idisk(1M), lvmadm(1M), pvcreate(1M), scsimgr(1M), vgchange(1M), vgdisplay(1M), vgextend(1M), vgreduce(1M), envi-
ron(5), lang(5), intro(7), lvm(7).
vgcreate(1M)