Extending a logical volume in a virtual machine running Red Hat or Cent OS

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Extending a logical volume in a virtual machine running Red Hat or Cent OS

Symptoms

increase-size

Purpose

This article provides steps for extending the root partition residing in a logical volume created with Logical Volume Manager (LVM) in a virtual machine running Red Hat/Cent OS.

Resolution

To extend the logical volume:

Note: These steps only apply to EXT3 file systems.

 

Caution: VMware recommends having a complete backup of the virtual machine prior making these changes.

1.       Power off the virtual machine.

2.       Edit the virtual machine settings and extend the virtual disk size. For more information, see Increasing the size of a virtual disk (1004047).

3.       Power on the virtual machine.

4.       Identify the device name, which is by default /dev/sda, and confirm the new size by running the command:

fdisk -l

5.       Create a new primary partition:

6.        

a.       Run the command:

fdisk /dev/sda (depending the results of the step 4)
 

b.       Press p to print the partition table to identify the number of partitions. By default there are 2: sda1 and sda2.

c.        Press n to create a new primary partition. 

d.       Press p for primary.

e.       Press 3 for the partition number, depending the output of the partition table print.

f.         Press Enter two times.

g.       Press w to write the changes to the partition table.

7.       Restart the virtual machine.

8.       Run this command to verify that the changes were saved to the partition table and that the new partition has an 83 type:

fdisk -l

9.       Run this command to convert the new partition to a physical volume:

pvcreate /dev/sda3

10.    Run this command to extend the physical volume:

vgextend VolGroup00 /dev/sda3

11.    Run this command to verify how many physical extents are available to the Volume Group:

vgdisplay VolGroup00 | grep "Free"

12.    Run the following command to extend the Logical Volume:

lvextend -L+#G /dev/VolGroup00/LogVol00

Where # is the number of Free space in GB available as per the previous command.

13.    Run the following command to expand the ext3 filesystem online, inside of the Logical Volume:

ext2online /dev/VolGroup00/LogVol00

Note: Use resize2fs instead of ext2online if it is not a Red Hat virtual machine.

14.    Run the following command to verify that the / filesystem has the new space available:

df -h /