Overview

A great benefit of the cloud servers is the easy scaling of resources up and down. But after scaling to a larger cloud machine and acquiring more storage space, you should extend the Linux partitions on it as well as the file system, in order to use that new space.

The tricky part here comes when you want to resize the root partition and some old methods included taking your server off, mounting the storage drive on another Linux machine and resizing the partitions. That of course is very inconvenient in the case of a production server and there are better ways to resize your root partition without having to take it offline.

In this tutorial we will see how to easily resize an online root partition on Ubuntu 16.04 without unmounting and so on.

Step 1: Resizing the partition

We are resizing the root partition which in the beginning is 30G.

root@cloud:~# df -h
Filesystem                  Size  Used Avail Use% Mounted on
udev                        473M     0  473M   0% /dev
tmpfs                        99M  3.1M   96M   4% /run
/dev/mapper/cloud–vg-root   30G  1.6G   27G   6% /
tmpfs                       492M     0  492M   0% /dev/shm
tmpfs                       5.0M     0  5.0M   0% /run/lock
tmpfs                       492M     0  492M   0% /sys/fs/cgroup
/dev/sda2                   473M   69M  381M  16% /boot
/dev/sda1                   511M  3.6M  508M   1% /boot/efi
tmpfs                        99M     0   99M   0% /run/user/0

The actual resize is done using the parted tool:

parted /dev/sda resizepart 3 100%

Step 2: Resizing physical volume

Now after we’ve resized the partition, we need to scale the physical volume:

pvresize /dev/sda3

Step 3: Resizing logical volume

Resize the logical volume goes like this:

root@cloud:~# lvextend -l +100%FREE /dev/cloud-vg/root
Size of logical volume cloud-vg/root changed from 30.02 GiB (7684 extents) to 62.02 GiB (15878 extents).
Logical volume root successfully resized.

Step 4: Resizing the file system

Last step is extend the file system:

resize2fs -p /dev/cloud-vg/root

The result of the df command now should be showing the new size:

root@cloud:~# df -h
Filesystem                  Size  Used Avail Use% Mounted on
udev                        473M     0  473M   0% /dev
tmpfs                        99M  3.1M   96M   4% /run
/dev/mapper/cloud–vg-root   61G  1.7G   57G   3% /
tmpfs                       492M     0  492M   0% /dev/shm
tmpfs                       5.0M     0  5.0M   0% /run/lock
tmpfs                       492M     0  492M   0% /sys/fs/cgroup
/dev/sda2                   473M  132M  317M  30% /boot
/dev/sda1                   511M  3.6M  508M   1% /boot/efi
tmpfs                        99M     0   99M   0% /run/user/0

Final thoughts

This easy and quick online resizing procedure can be used to expand live partition on your cloud servers.