Quick Reference of LVM

Last modified: Jan, 2010

Grow logic volume

The basic steps are like this: check free space –> expand logic volume –> expand file system. It can be done even with file system mounted.

• 1. Check the mounted file system with

df -h 

• 1. Check the available logic volumes

sudo lvdisplay 

• 1. Check how much free space available in this volume group for the growth

sudo vgdisplay 

• 1. Now resize the logic volume up to some point (of course within the free space limit)

sudo lvresize -L +1GB /dev/mapper/vg-xxx/yyy 

• 1. Check the new size of the logic volume

sudo lvdisplay 

• 1. Expand the existing file system to the size of logic volume

sudo resize2fs -p /dev/mapper/vg-xxx/yyy 

This command works for both ext2 and ext3 file systems.

Shrink logic volume

The order of shrinking is just the reverse of expanding: umount the file system –> check file system integrity –> shrink file system –> shrink logic volume.

• 1. First unmount the file system

sudo umount /yyy 

and get rid of any “device is busy” stuff.

• 1. Check the file system integrity

sudo e2fsck -f /dev/mapper/vg-xxx/yyy 

• 1. Shrink the file system to some point

sudo resize2fs /dev/mapper/vg-xxx/yyy 2000M 

Here it goes down to 2G, but above the physical size of existing files. This command works for both ext2 and ext3.

• 1. Shrink the logic volume

sudo lvresize -L -1G /dev/mapper/vg-xxx/yyy 

Here the logic volume is shrunk by 1G. The left space should not be smaller than that of the file system. Do the math.

• 1. Expand the file system to fit the shrunk logic volume

sudo resize2fs -p /dev/mapper/vg-xxx/yyy 

• 1. Remount the file system.

How to grow logic volume to the maximum available space

sudo lvresize -l +100%FREE