|
|
AIX and DS4300 Storage Unit
|
|
vgchgid(1M) vgchgid(1M) NAME
vgchgid - modify the Volume Group ID (VGID) on a given set of physical devices SYNOPSIS
PhysicalVolumePath [PhysicalVolumePath] ... DESCRIPTION
The command is designed to change the LVM Volume Group ID (VGID) on a supplied set of disks. will work with any type of storage, but it is primarily targeted at disk arrays that are able to create "snapshots" or "clones" of mirrored LUNs. accepts a set of raw physical devices and ensures that they all belong to the same volume group, before altering the VGID (see section). The same VGID is set on all the disks and it should be noted that in cases of multi-PV volume groups, all the physical volumes should be supplied in a single invocation of the command. Options recognizes the following options and arguments: PhysicalVolumePath The raw devices path name of a physical volume. Background Some storage subsystems have a feature which allows a user to split off a set of mirror copies of physical storage (termed or just as LVM splits off logical volumes with the command. As the result of the "split," the split-off devices will have the same VGID as the original disks. 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 WARNINGS
Once the VGID has been changed, the original VGID is lost until a disk device is re-mirrored with the original devices. If is used on a subset of disk devices (for example, two out of four disk devices), the two groups of disk devices would not be able to be imported into the same volume group since they have different VGIDs on them. The solution is to re-mirror all four of the disk devices and re-run on all four BCV devices at the same time, and then use to import them into the same new volume group. If a disk is newly added to an existing volume group and no subsequent LVM operations has been performed to alter the structures (in other words, operations which perform an automated vgcfgbackup(1M)); then it is possible a subsequent 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 It is the system administrator's responsibility to make sure that the devices provided in the command line are all Business Copy volumes of the existing standard physical volumes and are in the ready state and writable. Mixing the standard and BC volumes in the same volume group can cause data corruption. RETURN VALUE
returns the following values: 0 VGID was modified with no error 1 VGID was not modified EXAMPLES
An example showing how 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 and 2) For XP disk array, the commands are and Three BCV disks are created. 2. Change the VGID on the BCV disks. 3. Make a new volume group using the BCV disks. This step can be skipped as the group file will be created automatically. If the file is manually created it will have different major and minor numbers (see lvm(7)). 4. Import the BCV disks into the new volume group. 5. Activate the new volume group. 6. Backup the new volume group's LVM data structure. 7. Mount the associated logical volumes. SEE ALSO
vgimport(1M), vgscan(1M), vgcfgbackup(1M). vgchgid(1M)
