lvm concept

[sriprabhu]

Hai

i need a lvm concept document if you have please send it

[P Arumugavel]

Hi,

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

[Viktor Balogh]

@Vel-UX:

don't forget the credits:

http://blogs.neuronring.com/blogs/computer/unix-and-linux/logical-volume-manager-lvm-configuration/

@sriprabhu:

see also "man 7 lvm" or

http://docs.hp.com/en/B9106-90013/lvm.7.html

[Ishwar_1]

Overview of LVM Operation
=========================
Logical Volume Manager (LVM) is a subsystem for managing file systems and disk storage space that are structured into logical volumes rather than being restricted to the beginning and end points of a physical disk. Logical volumes can be smaller than the disk or disk array on which they reside, or they can include all or part of several disks or disk arrays. Logical volume boundaries are not required to coincide with the boundaries of physical disks when multiple disks or arrays are used.

Managing logical volumes is done by the Logical Volume Manager, not the kernel. However, the kernel contains data structures for each volume group on the system, and the space reserved for LVM data structures must be sufficient to support the number of volume groups that exist on the system. This is done by the maxvgs kernel configuration parameter. A second parameter, no_lvm_disks, is provided for notifying the kernel at boot time that no logical volumes exist on the system. This saves the system from having to identify and activate logical volumes at boot time.


LVM Architecture Overview.
==========================
http://www.centos.org/docs/5/html/Cluster_Logical_Volume_Manager/LVM_definition.html

Go through Below link to know basic concept about lvm.
===============================================
http://linux.web.cern.ch/linux/scientific5/docs/rhel/Cluster_Logical_Volume_Manager/LVM_CLI.html

Find Below Link for Some of Good HP-UX LVM technical Document
=======================================================
http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?lang=en&cc=us&taskId=101&prodClassId=10008&contentType=SupportManual&docIndexId=64255&prodTypeId=18964&prodSeriesId=4296010


Note :- Assign points once your query as been answered

Regards
Ishwar VenuGopal

[sriprabhu]

thanks

[sriprabhu]

thanks