What is Logical Volume Manager ?
HP-UX LVM is used to manage disk space with special features like mirroring, high availability, stripping, etc. Physical volumes can be organized into a logical volume groups with equal size extent.
Each volume group can have one or more physical volumes. A system can have more than single volume groups. A volume group can be moved from a system to another instead of physical disk.
A volume group can be divided into virtual disks, called logical volumes. A logical volume can span a number of physical volumes or represent only a portion of one physical volume. Disks can be added into logical volumes with different sizes.
The following commands are used to create, display and manipulate the LVM:
1. pvcreate
Creates physical volume to use in logical volume group.
Syntax: pvcreate -f /dev/rdsk/c2tod1
2. pvdisplay
Displays information about physical volumes in LVM volume group.
Syntax: pvdisplay /dev/dsk/c2tod1
3. pvmove
Move allocated physical extents frm one LVM physcal volume to another.
Syntax: pvmove /dev/dsk/c1t0d0 PVG0
4. vgcreate
Creates LVM volume group.
Syntax: Create a directory for volume group.
mkdir /dev/vg00
vgcreate -s 2 /dev/vg00 /dev/dsk/c1t0d0
5. vgdisplay
Display information about LVM volume groups.
Syntax: vgdisplay -v /dev/vg00
6. vgexport
Export an LVM volume group and its associated logical volumes.
Syntax: vgexport -v -f vg00.outfile /dev/vg00
7. vgimport
Import an LVM volume group onto the system.
Syntax: vgimport -v /dev/vg00 /dev/dsk/c0t1d0
8. vgextend
Extend an LVM volume group by adding physical volumes.
Syntax: vgextend /dev/vg00 /dev/dsk/c0t1d0
9. vgreduce
Remove physical volumes from an LVM volume group.
Syntax: vgreduce /dev/vg00 /dev/dsk/c0t1d0
10. vgremove
Remove LVM logical volume group from system.
Syntax: vgremove /dev/vg00 /dev/dsk/c0t1d0
11. vgscan
Scans physcal volumes for LVM volume group.
Syntax: vgscan
12. lvcreate
Creates logical volume in LVM volume group.
Syntax:
lvcreate -L 100 /dev/vg03
13. lvdisplay
Displays information about logical volumes .
lvdisplay /dev/vg00
14. lvextend
Increase space,mirrors for logical volumes.
lvextend -L 400 /dev/vg03
15. lvreduce
Reduce number of physical extents, mirrors.
lvreduce -L 50 /dev/vg03
16. lvremove
Remove one or more logical volumes from system.
lvremove -f /dev/vg03
17. lvlnboot
Prepare LVM logical volume to be root, boot, primary swap, or dump volume.
lvlnboot -r /dev/vg00
18. lvrmboot
Remove logical volume link to root, primary swap, or dump volume.
lvrmboot -r /dev/vg00
Regards,
R.Gopinath
