====== Ubuntu - LVM - Increase the capacity of an LVM volume group ======

To increase the capacity of an existing LVM volume group by adding more physical volumes.

Suppose that /dev/vg01 is a volume group composed of three 100GB physical volumes, giving it a total capacity of 300GB.  You wish to add two further physical volumes to increase the total capacity to 500GB.

The existing physical volumes are named /dev/sda, /dev/sdb and /dev/sdc.  The new ones are named /dev/sdd and /dev/sde.

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===== Prerequisites =====

With older versions of LVM it was necessary for physical volumes to be explicitly initialized using **pvcreate** before being added to a volume group.  As of version 2.02.54 this is no longer necessary because initialization will occur automatically if required.  Prior initialization may still be desirable in order to deviate from the default settings used by **pvcreate**, obtain better diagnostics by proceeding one step at a time, or retain compatibility with older versions of LVM.

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===== Method =====

Physical volumes can be added to a volume group using the **vgextend** command:

<code bash>
vgextend vg01 /dev/sdd /dev/sde
</code>

The first argument is the name of the volume group to be extended.  This can be written as a pathname if you prefer (/dev/vg01).  Subsequent arguments are the physical volumes to be added.

If successful you should see a response of the form:

<code>
Volume group "vg01" successfully extended
</code>

If the physical volumes have not previously been initialized using **pvcreate** then there will be some additional diagnostic messages, for example:

<code bash>
No physical volume label read from /dev/sdd
Physical volume "/dev/sdd" successfully created
No physical volume label read from /dev/sde
Physical volume "/dev/sde" successfully created
Volume group "vg01" successfully extended
</code>

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===== Testing =====

You can check the new capacity of the volume group using the **vgs** command:

<code bash>
vgs vg0
</code>

This should give a response of the form:

<code bash>
  VG   #PV #LV #SN Attr   VSize   VFree
  vg01    5   0   0 wz--n- 499.98G 499.98G
</code>  

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===== Next steps =====

The extra capacity added to the volume group should now be available for use, either by creating new logical volumes or by expanding the size of existing ones.  In the latter case, if the logical volume contains a filesystem then you will probably want to expand that too.  See:

Increase the size of an LVM logical volume
Increase the size of an ext2, ext3 or ext4 filesystem
for details of some of these processes.

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===== See also =====

  * [[Ubuntu:LVM:Replace one of the physical volumes in an LVM volume group|Replace one of the physical volumes in an LVM volume group]]

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===== Troubleshooting =====

  * [[Ubuntu:LVM:Troubleshooting LVM|Troubleshooting LVM]]