Expanding Logical Volumes in Linux

This article will detail the steps for both scenarios. The main steps are as follows:

In this case, we need to expand the logical volume mylv under the volume group textvg by 100G, and the remaining space in the volume group is 120G

To confirm the logical volume’s name, size, and the remaining space in the volume group

lvdisplay /dev/datavg/mylv

Use the <span>lvextend</span> command to expand the logical volume. You can use <span>-L</span> to specify the absolute size of the logical volume, or use <span>-l</span> to specify the number of physical extents (PE, generally each PE is 4MB in size). However, it is usually sufficient to use <span>-L</span>.

lvextend -L +100G /dev/datavg/mylv

# or
lvextend -l 250 /dev/datavg/mylv

# If you want to use all remaining space, you can use the following command
lvextend -l +100%FREE /dev/datavg/mylv

After expanding the logical volume, the next step is to expand the file system to utilize the newly added space. Depending on the file system type used, use the corresponding command. Here we are using the xfs file system

# For xfs system:
xfs_growfs /dev/datavg/mylv

# For ext4 system:
resize2fs /dev/datavg/mylv

Finally, check the sizes of the logical volume and file system to confirm whether the expansion was successful.

df -Th
# or
lvdisplay /dev/datavg/mylv

If the existing volume group has insufficient remaining space (check using <span>vgs</span>), we can expand the physical volume of the volume group by adding a new physical disk, and then add the new space to the volume group to meet the expansion requirements. Here we take the local virtual machine sda system disk expansion as an example; if it is a cloud server, you can choose the cloud disk expansion service. The steps for expanding the logical volume are the same. Here, we will expand the root logical volume of the centos volume group by 10G

Shut down the virtual machine, select edit virtual machine – hard disk – expand – enter the maximum disk size – start after expansion

1. Use <span>fdisk /dev/sda </span>to create a partition,
2. Enter <span>n</span> (new partition),
3. <span>p (partition number, default is 3),</span>
4. Press enter (select the starting sector, usually the default is fine),
5. Press enter (you can choose the partition size),
6. <span>w (save and exit).</span>
7. Then use <span>lsblk</span> to check the block device information. If <span>lsblk</span> does not show the newly created partition (i.e., sda3), use the <span>partprobe</span> command.

1. <span>fdisk /dev/sda (manage disk partitions),</span>
2. <span>t (change type of partition number),</span>
3. Press enter (because the partition number defaults to 3, which is consistent with the partition number when created, so just press enter),
4. Input hex code option 8e, <span>w</span> (save and exit), changing the partition type to Linux LVM
5. Use <span>fdisk -l</span> to check if it has taken effect

pvcreate /dev/sda3

vgextend centos /dev/sda3

lvextend -L +10G /dev/centos/root

# For xfs system:
xfs_growfs /

# For ext4 system:
resize2fs /dev/mapper/centos-root

df -Th