====== Resize LVM ======


=== Creating a new Logical Volume ===

In this example we will create a new logical volume called **wworks**, mounted at **/wworks** which will be part of the **vg00** Volume Group at **/dev/mapper/vg00-lv_wworks**

1. Check to see how much free space you have to allocate the new logical volume:
  [root@gi-rgs-rng01 /]# vgdisplay | egrep 'Name|Free'
    VG Name               vg00
    Free  PE / Size       2515 / 78.59 GB

2. Create the new logical volume and assign it to the vg00 volume group:
  [root@gi-rgs-rng01 /]# lvcreate -L 30G -n lv_wworks vg00
    Logical volume "lv_wworks" created

3. Format it with a journalled filesystem:
  mkfs.ext3 -j /dev/mapper/vg00-lv_wworks
  
4. Add the new entry to fstab (use the others as a template):
  [root@gi-rgs-rng01 /]# cat /etc/fstab | grep wworks
  /dev/vg00/lv_wworks     /wwworks                ext3    defaults        1 2

5. Mount the new logical volume and test it:
  [root@gi-rgs-rng01 /]# mount -a && df -h | egrep 'File|wworks' && echo "test">/wworks/neil.test && cat /wworks/neil.test
  Filesystem            Size  Used Avail Use% Mounted on
  /dev/mapper/vg00-lv_wworks
                       30G   76M   28G   1% /wworks
  test

6. You can also see it as a member of the vg00 Volume Group:
  [root@gi-rgs-rng01 /]# lvs
  LV        VG   Attr   LSize  Origin Snap%  Move Log Copy%  Convert
  lv_home   vg00 -wi-ao 10.00G
  lv_log    vg00 -wi-ao 10.00G
  lv_root   vg00 -wi-ao 15.00G
  lv_swap   vg00 -wi-ao  5.88G
  lv_tmp    vg00 -wi-ao  2.00G
  lv_var    vg00 -wi-ao 15.00G
  lv_wworks vg00 -wi-ao 30.00G


  
  
=== Reducing the size of an LVM ===

In this example we will reduce the size of **/var/log** which is an LV at **/dev/mapper/vg00-lv_log**

  [root@gi-rgs-rng01 /]# df -h | egrep 'Filesystem|log'
  Filesystem            Size  Used Avail Use% Mounted on
  /dev/mapper/vg00-lv_log
                       50G   85M   47G   1% /var/log


1. Ensure the filesystem is unmounted
  $ umount /var/log

2. If the mount point is in use try identifying what's using it with lsof:
  $ lsof | grep "/var/log"

3. Ensure /var/log is no longer mounted.
  $ df -h | grep "/var/log"
//
//
**Ensure the amount of data contained within the LV does not exceed the size you will be reducing it to or this will result in data loss.**
//
//

4. First the filesystem needs to be checked.
  [root@gi-rgs-rng01 /]# e2fsck -f /dev/mapper/vg00-lv_log
  e2fsck 1.35 (28-Feb-2004)
  Pass 1: Checking inodes, blocks, and sizes
  Pass 2: Checking directory structure
  Pass 3: Checking directory connectivity
  Pass 4: Checking reference counts
  Pass 5: Checking group summary information
  /dev/mapper/vg00-lv_log: 56/6553600 files (19.6% non-contiguous), 227290/13107200 blocks
  
5. Now reduce the filesystem to 10GB.
  [root@gi-rgs-rng01 /]# resize2fs /dev/mapper/vg00-lv_log 10G
  resize2fs 1.35 (28-Feb-2004)
  Resizing the filesystem on /dev/mapper/vg00-lv_log to 2621440 (4k) blocks.
  The filesystem on /dev/mapper/vg00-lv_log is now 2621440 blocks long.
  
6. Now reduce the size of the LV:
  [root@gi-rgs-rng01 /]# lvreduce -L 10G /dev/mapper/vg00-lv_log
    WARNING: Reducing active logical volume to 10.00 GB
    THIS MAY DESTROY YOUR DATA (filesystem etc.)
  Do you really want to reduce lv_log? [y/n]: y
    Reducing logical volume lv_log to 10.00 GB
    Logical volume lv_log successfully resized
  
7. Remount the partition and check the new size is correct:
  [root@gi-rgs-rng01 /]# mount -a ; df -h | egrep 'Filesystem|log'
  Filesystem            Size  Used Avail Use% Mounted on
  /dev/mapper/vg00-lv_log
                      9.9G   69M  9.3G   1% /var/log
                      
                      

=== Extending the size of a Logical Volume ===

In this example we will extend the size of **/wworks** which is an LV at **/dev/mapper/vg00-lv_wworks**, to 50GB.

1. Ensure the filesystem is unmounted
  $ umount /wworks

2. If the mount point is in use try identifying what's using it with lsof:
  $ lsof | grep "/wworks"

3. Ensure /var/log is no longer mounted.
  $ df -h | grep "/wworks"

4. Extend the size of the logical volume:
  $ lvextend -L 50GB /dev/mapper/vg00-lv_wworks

5. Now extend the filesystem to that new size
  $ resizefs /dev/mapper/vg00-lv_wworks 50G
  
6. Remount the partition and check the new size is correct:
  $ mount -a ; df -h | egrep 'Filesystem|wworks'