Sets the characteristics of a volume group.
chvg [ -s Sync { y | n }] [ -h Hotspare {y | Y | n | r }] [ -a AutoOn { n | y } ] [ -c | -l ] [ -L LTGSize ] [ -Q { n | y } ] [ -u ] [ -x { n | y } ] [ -S | -R] [ -t [factor ] ] [ -B ] [ -C ]VolumeGroup
The chvg command specifies whether or not the volume group is automatically activated during the system startup. If there is a volume group that is infrequently used, you may not want it activated at system startup because it uses kernel resources (memory).
MAXPVS 32 (128 if -B flag is used)
Note: To use this command, you must either have root user authority or be a member of the system group.
You can use the Volumes application in Web-based System Manager (wsm) to change volume characteristics. You could also use the System Management Interface Tool (SMIT) smit chvg fast path to run this command.
-a AutoOn | Determines if the volume group is automatically activated during system
startup. The AutoOn variable can be either of the
following:
|
-B | Changes the volume group to big vg format. This can accommodate up
to 128 physical volumes and 512 logical volumes.
Notes: |
-c | Changes the volume group into a Concurrent Capable or Enhanced Concurrent
Capable volume group. However, the volume group must be varied on in
non-concurrent mode for this command to take effect. This requires that
the volume group be reimported on all other nodes for the change to take
affect. The -c flag is only supported with HACMP and HACMP
ES. This flag has no effect on volume groups and systems not using one
of these HACMP products.
The Concurrent Capable volume group is only supported on Serial DASD and SSA disks. The Enhanced Concurrent Capable volume group is supported for all other disk types.
Notes: |
-C | Changes the volume group into an Enhanced Concurrent Capable volume
group. Changes the volume group varied on in non-concurrent mode to
Enhanced Concurrent Capable. This requires that the volume group be
reimported on all other nodes prior to activation in Enhanced Concurrent
mode. Changes the volume group varied on in Concurrent mode to an
Enhanced Concurrent mode volume group. Only use the -C flag
with the HACMP ES. It has no effect on volume groups and systems not
using the HACMP ES product.
Enhanced Concurrent volume groups use Group Services. Group Services ships with HACMP ES and must be configured prior to activating a volume group in this mode. Use this flag to change a volume group containing Serial DASD or SSA disks into an Enhanced Concurrent Capable volume group.
Notes: |
-h Hotspare | Sets the sparing characteristics for the volume group specified by the
VolumeGroup parameter. Either allows (y) the
automatic migration of failed disks, or prohibits (n) the automatic
migration of failed disks. This flag has no meaning for non-mirrored
logical volumes
Note: This flag is not supported for the concurrent capable volume groups. |
-l | Changes the volume group into a Non-Concurrent Capable volume group. The volume group must be varied on in non-concurrent mode for this command to take effect. This flag only applies to AIX 4.3 or later. |
-L | Changes the logical track group size, in number of kilobytes, of the
volume group. The value of the LTGSize parameter must be
128, 256, 512, or 1024. In addition, it should be less than or equal to
the maximum transfer size of all disks in the volume group. The default
size is 128 kilobytes.
Notes: |
-Q | Determines if the volume group is automatically varied off after losing
its quorum of physical volumes. The default value is yes. The
change becomes effective the next time the volume group is activated.
Note: Quorum must be turned on for Enhanced Concurrent Capable volume groups.
|
-R | Resumes normal I/O operations for a volume group. |
-s Sync | Sets the synchronization characteristics for the volume group specified
by the VolumeGroup parameter. Either permits (y)
the automatic synchronization of stale partitions or prohibits (n)
the automatic synchronization of stale partitions. This flag has no
meaning for non-mirrored logical volumes.
Note: This flag is not supported for the concurrent capable volume groups. |
-S | Drains I/O's for this volume group and suspends future I/O's. |
-t [factor] | Changes the limit of the number of physical partitions per physical
volume, specified by factor. factor should be
between 1 and 16 for 32 disk volume groups and 1 and 64 for 128 disk volume
groups.
If factor is not supplied, it is set to the lowest value such that the number of physical partitions of the largest disk in volume group is less than factor x 1016. If factor is specified, the maximum number of physical partitions per physical volume for this volume group changes to factor x 1016.
Notes: |
-u | Unlocks the volume group. This option is provided if the volume
group is left in a locked state by abnormal termination of another LVM
operation (such as the command core dumping, or the system crashing).
Note: Before using the -u flag, make sure that the volume group is not being used by another LVM command. |
-x | Changes the mode which the Concurrent Capable volume group is varied
on. The volume group must be varied on in non-concurrent mode for this
command to take effect. This flag only applies to AIX 4.2 or
later.
Note: There is no auto on support for Enhanced Concurrent Capable volume groups.
Note: If the volume group is not created Concurrent Capable, this command has no effect on the volume group.
In order for this auto-varyon into concurrency of the volume group to take effect, you must enter the following line into the /etc/inittab file: rc_clvmv:2:wait:/usr/sbin/clvm_cfg 2>&1
Attention: This entry must be added after the entry used to initiate srcmstr. |
/usr/sbin | Directory where the chvg command resides. |
Commands: bosboot, lsvg, mkvg, savebase, varyonvg.
The Logical Volume Storage Overview in AIX 5L Version 5.1 System Management Concepts: Operating System and Devices explains the Logical Volume Manager, physical volumes, logical volumes, volume groups, organization, ensuring data integrity, and allocation characteristics.
For information on installing the Web-based System Manager, see Chapter 2: Installation and System Requirements in AIX 5L Version 5.1 Web-based System Manager Administration Guide.
The System Management Interface Tool (SMIT): Overview in AIX 5L Version 5.1 System Management Concepts: Operating System and Devices explains the structure, main menus, and tasks that are done with SMIT.