PRELIMINARIES TO ENLARGING A VOLUME IN LINUX:

1) First you will want to type a few commands to make sure that you have enough free volume space to enlarge your volume.
   a) First open a terminal
   b) #su -  (type this to make yourself super user/administrator)
   c) type in your root/administrator password
   d) type in the command below
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[root@mikebeaver ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                      9.9G  9.3G  144M  99% /
/dev/sda1              99M   14M   80M  15% /boot
tmpfs                 506M     0  506M   0% /dev/shm
/dev/hda1              49G   37G   12G  76% /media/c_drive
/dev/hda5             139G   80G   59G  58% /media/d_drive
/dev/hdd              1.4M   56K  1.4M   4% /media/floppy
/dev/hdc              489M  489M     0 100% /media/WXPVOL_EN
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From the above output, you can see that the /boot partition is 15 percent of the logical volume VolGroup00-LogVol00.
But this doesn't tell you what is on the rest of the 85% of the logical volume that isn't mentioned.
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   c) type in the command below:
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[root@mikebeaver ~]# lvdisplay -vv
      Setting global/locking_type to 1
      Setting global/locking_dir to /var/lock/lvm
      File-based locking enabled.
    Finding all logical volumes
      /dev/root: No label detected
      /dev/hda1: No label detected
      /dev/sda1: No label detected
      /dev/VolGroup00/LogVol01: No label detected
      /dev/sda2: lvm2 label detected
      /dev/hda5: No label detected
      Locking /var/lock/lvm/V_VolGroup00 RB
      /dev/sda2: lvm2 label detected
      /dev/sda2: lvm2 label detected
  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol00
  VG Name                VolGroup00
  LV UUID                f6MqMw-JXRS-MHmu-926b-Pc2s-192D-ERZyYx
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                10.22 GB
  Current LE             327
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:0

  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol01
  VG Name                VolGroup00
  LV UUID                FnBomF-MTw8-yHYx-As4w-Qajf-Xxvk-mGTtFk
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                1.94 GB
  Current LE             62
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:1

      Unlocking /var/lock/lvm/V_VolGroup00
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From the output (above), you can see that one volume is 10.22 GB and the other volume is 1.94 GB in size.
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[root@mikebeaver ~]# vgdisplay
  --- Volume group ---
  VG Name               VolGroup00
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               93.25 GB
  PE Size               32.00 MB
  Total PE              2984
  Alloc PE / Size       389 / 12.16 GB
  Free  PE / Size       2595 / 81.09 GB
  VG UUID               L7X2cx-n1qO-m7NH-gJnw-XiKW-lx2a-AXdqEv
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From the (above) output, you can see that the volume group size is 93.25 GB.
You can also see that, of that 93.25 GB in volume group size, 12.16 GB has been allocated.
And, you also see that there's 81.09 GB free.
That meens you can extend the used volume space by approximately 81G.
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To enlarge a volume, in Linux, type the following two sets of commands (no need for the help command), at the terminal # prompt.

the command to extend is:

#lvextend -L20G /dev/VolGroup00/LogVol00   (that extends the volume to 20G)

#lvextend --help                           (for other possibilities)

Once you have extend the logical volume, you have to grow the filesystem. 
with:

#ext2online /dev/VolGroup00/LogVol00  
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