vgchgid - modify the Volume Group ID (VGID) on a given set of physical
/usr/sbin/vgchgid PhysicalVolumePath [PhysicalVolumePath] ...
The vgchgid command is designed to change the LVM Volume Group ID
(VGID) on a supplied set of disks. It is primarily targeted for disk
arrays which have capability of creating mirrored Business Copy (BC),
such as EMC Symmetrix disks, and the XP disk array family, such as
XP256 and XP512. vgchgid command accepts a set of raw physical
devices and checks the following criteria before it alters the VGID:
+ All raw physical volume devices in the command line have the same
disk type, such as:
1) EMC Symmetrix disks with the BCV attributes. (See EMC
2) The XP disk array family with BC_SVOL or CA_SVOL attributes.
(See XP256/XP512 related documentation.)
+ All raw physical volume devices in the command line belong to the
same VG. (See WARNINGS section.)
Once the checks are successful, the same VGID is set on all the disks.
It should be noted that for multi-PV volume groups all the physical
volumes should be split-off and supplied in a single invocation of the
vgchgid recognizes the following options and arguments:
PhysicalVolumePath The raw devices path name of a physical
Both the EMC and XP disk arrays have a feature which allows a user to
split-off a set of mirrored copies of physical volumes (termed BCVs or
BCs) just as LVM split-off logical volumes with lvsplit command. As
the result of the "split," the split-off devices will have the same
VGID as the original disks. The vgchgid command is needed to modify
the VGID on the BCV devices. Once the VGID has been altered, the BCV
disks can be imported into a new volume group by using the vgimport
Once the VGID has been changed, the original VGID is lost until a BCV
device is re-mirrored with the original devices. If the vgchgid
command is used on a subset of BCV devices (e.g., two out of four BCV
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devices), the two groups of BCV devices would not be able to be
imported into the same VG since they have different VGID on them. The
solution is to re-mirror all four of the BCV devices and re-run the
vgchgid command on all four BCV devices at the same time, and then use
the vgimport command to import them into the same new VG.
If a disk is newly added to an existing volume group and no subsequent
LVM operations has been performed to alter the structures (i.e.,
operations which perform an automated vgcfgbackup(1M)); then it is
possible a subsequent vgchgid will fail. It will report that the disk
does not belong to the volume group. This may be overcome by
performing a structure changing operation on the volume group (for
example, using lvcreate).
vgchgid command returns the following values:
0 VGID was modified with no error
1 VGID was not modified
An example showing how vgchgid command might be used.
1. The system administrator uses the following commands to create the
Business Continuity (BCV or BC) copy:
1) For EMC Symmetrix disks, the commands are BCV establish and
2) For XP disk array, the commands are paircreate and pairsplit.
Three BCV disks are created.
2. Change the VGID on the BCV disks.
vgchgid /dev/rdsk/c0t0d0 /dev/rdsk/c0t0d1 /dev/rdsk/c0t0d2
3. Make a new volume group using the BCV disks.
mknod /dev/vgbcv/group c 64 0x040000
4. Import the BCV disks into the new volume group.
vgimport /dev/vgbcv /dev/dsk/c0t0d0 /dev/dsk/c0t0d1 /dev/dsk/c0t0d2
5. Activate the new volume group.
vgchange -a y /dev/vgbcv
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6. Backup the new volume group's LVM data structure.
7. Mount the associated logical volumes.
mkdir /bcv/lvol1 /bcv/lvol2
mount /dev/vgbcv/lvol1 /bcv/lvol1
mount /dev/vgbcv/lvol2 /bcv/lvol2
vgimport(1M), vgscan(1M), vgcfgbackup(1M).
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