Moving A Volume Group To Another System; Recreating A Volume Group Directory; Logical Volume Administration - Red Hat ENTERPRISE LINUX 5 - LOGICAL VOLUME MANAGER ADMINISTRATION Manual

Chapter 4. LVM Administration with CLI Commands

4.3.14. Moving a Volume Group to Another System

You can move an entire LVM volume group to another system. It is recommended that you use the
vgexport and vgimport commands when you do this.
The vgexport command makes an inactive volume group inaccessible to the system, which allows
you to detach its physical volumes. The vgimport command makes a volume group accessible to a
machine again after the vgexport command has made it inactive.
To move a volume group form one system to another, perform the following steps:
1. Make sure that no users are accessing files on the active volumes in the volume group, then
unmount the logical volumes.
2. Use the -a n argument of the vgchange command to mark the volume group as inactive, which
prevents any further activity on the volume group.
3. Use the vgexport command to export the volume group. This prevents it from being accessed by
the system from which you are removing it.
After you export the volume group, the physical volume will show up as being in an exported
volume group when you execute the pvscan command, as in the following example.
[root@tng3-1]# pvscan
PV /dev/sda1
PV /dev/sdc1
PV /dev/sdd1
...
When the system is next shut down, you can unplug the disks that constitute the volume group
and connect them to the new system.
4. When the disks are plugged into the new system, use the vgimport command to import the
volume group, making it accessible to the new system.
5. Activate the volume group with the -a y argument of the vgchange command.
6. Mount the file system to make it available for use.

4.3.15. Recreating a Volume Group Directory

To recreate a volume group directory and logical volume special files, use the vgmknodes command.
This command checks the LVM2 special files in the /dev directory that are needed for active logical
volumes. It creates any special files that are missing removes unused ones.
You can incorporate the vgmknodes command into the vgscan command by specifying the mknodes
argument to the vgscan command.

4.4. Logical Volume Administration

This section describes the commands that perform the various aspects of logical volume
administration.
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is in exported VG myvg [17.15 GB / 7.15 GB free]
is in exported VG myvg [17.15 GB / 15.15 GB free]
is in exported VG myvg [17.15 GB / 15.15 GB free]