Logical Volume Manager (LVM). Part 3 Commands

Command to gather information about file systems, the structure of the LVM, etc.:

•  bdf -list of mounted file systems.
•  ls -ltra /*/group  -cool command to view control files of all Volume Groups on the server.
   Is often useful when finding free minor-rooms for the new Volume Group.
•  lvdisplay -v/dev/vg01/lvol1 -information about Logical Volume, you can try lvol1 general case:
•  cat /etc/fstab -a list of all the file systems that are mounted at startup OS
•  vgdisplay -v - information about all Volume Groups
•  vgdisplay-v vg01 -  information about the specific group.
•  lvdisplay -v/dev/vg01/lv * -information about all Logical Volume from a Volume Group vg01.
• pvdisplay -v /dev/dsk/c1t1d2 -information on the Physical Volume.

Expansion Volume Group (adding disk) Logical Volume:

1.  pvcreate -f /dev/rdsk/c1t1d2 -to prepare a disk for connecting to LVM,
2.  vgextend vg01 /dev/dsk/c1t1d2 -add to an existing Volume Group vg01 new drive.
3.  lvextend -L /dev/vg01/lvol1 48000 -extend Logical Volume size to 48000 lvol1 MB.

Extend filesystem on lvol1 (prior to this event, though the drive (Logical Volume) and became more,
 but the file system will not be able to use it):

• umount /data -unmount file system
• extendfs -F vxfs/dev/vg01/rlvol1 -extend the file system on any space
• mount /data -mount extended file system
• bdf -check out the new size.

Reducing of the file system and Logical Volumes is very rare operation, because prior to this,
you must delete the data by making a backup, and after you reduce the file system and Logical Volume commands newfs and lvreduce command.

Commands to delete Logical Volume:

1.  umount /data -unmount file system
2.  lvremove -f /dev/vg01/lvol1 -remove a Logical Volume with option "force" (in spite of
    the existence of the file system and data)
3.  vi /etc/fstab -edit the list of mounted file systems in Windows is restarted,
4.  vgdisplay -v vg01 -verify that Logical Volume.

Remove a physical disk from a Volume Group:

1.  pvmove/dev/dsk/c1t1d2 /dev/dsk/c1t2d1 -move data from disk c1t1d2 on another
    disk in the Volume Group (if you do not specify a second disk, the command will place itself
    on the remaining disks in the Volume Group, of course, subject to the availability of places on them),
2.  pvdisplay -v /dev/dsk/c1t1d2 -check that there is no data on the disk (a single physical
    extent-PE)
3.  vgreduce vg01 /dev/dsk/c1t1d2 -remove the disk from the Volume Group vg01,
4.  vgdisplay -v vg01 -check changes.

Removing a Volume Group:

1.  lvremove -f /dev/vg01/lvol1 -remove all Logical Volumes,
2.  vgreduce vg01/dev/dsk/c1t1d2 -remove all but one of the disks
3.  vgremove vg01 -Delete Volume Group vg01,
4.  rm-irf/dev/vg01 - force remove of a directory vg01.

You can remove a single command: 
-  vgexport/dev/vg01 - remove everything about anything without asking. :)

Activation and deactivation of the Volume Group:

•  vgchange-a n vg01 -deactivates the Volume Group vg01, removing it from the LVM kernel
   tables,
•  vgchange-a y vg01 -activates the Volume Group vg01, making possible the mounting of
   file systems (automatic activation is performed when Windows is restarted)
•  vgchange-a r vg01 -activate Volume Group vg01 in read-only mode.

Command sequences are correct for the file systems HFS, JFS. There is an additional option,
which can be purchased at the HP Online JFS. There's "cool things"  like reducing - extending
the file system without unmount etc. The main command - fsadm.