HP-UX Reference (11i v1 00/12) - 1M System Administration Commands N-Z (vol 4)
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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man1m/naaagt.1m
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v
vgchgid(1M) vgchgid(1M)
NAME
vgchgid - modify the Volume Group ID (VGID) on a given set of physical devices
SYNOPSIS
/usr/sbin/vgchgid PhysicalVolumePath [PhysicalVolumePath] ...
DESCRIPTION
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 documentation.)
2) The XP disk array family with BC_SVOL or CA_SVOL attributes. (See XP256/XP512 related docu-
mentation.)
• 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 command.
Options
vgchgid recognizes the following options and arguments:
PhysicalVolumePath The raw devices path name of a physical volume.
Background
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
BCVsorBCs) 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 command.
WARNINGS
Once the VGID has been changed, the original VGID is lost until a BCV device is re-mirrored with the ori-
ginal devices. If the
vgchgid command is used on a subset of BCV devices (e.g., two out of four BCV dev-
ices), 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 per-
formed 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).
RETURN VALUE
vgchgid command returns the following values:
0 VGID was modified with no error
1 VGID was not modified
EXAMPLES
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 BCV split.
2) For XP disk array, the commands are paircreate and pairsplit.
Three BCV disks are created.
HP-UX Release 11i: December 2000 − 1 − Section 1M−−1013
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