How to resize the root partition and create a new data partition Print

In this tutorial, we will go through the process of shrinking the root partition of a Linux server and creating a new data partition in the freed space.

Step 1 - Boot into the Rescue System

If you haven't already, boot the server into the Rescue System. Ensure that the root partition is not mounted. E.g. check with:

lsblk

If the root partition is mounted, it will look something like this:

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 38.1G 0 disk
├─sda1 8:1 0 20.2G 0 part /
...

Step 2 - Resize the Partition

Check and Shrink the Filesystem

Run the following commands to check and shrink the filesystem:

e2fsck -f -y /dev/sda1
resize2fs /dev/sda1 20G

This reduces the root filesystem to 20 GB.

Adjust the Partition

Resize the root partition to a slightly larger size than the filesystem to allow some buffer (22 GB in this case):

parted /dev/sda
(parted) print
(parted) resizepart 1 22GB
(parted) quit

Repair the Filesystem

e2fsck -f -y /dev/sda1

This verifies and repairs the resized filesystem.

Create a New Partition

Use the remaining free space for a new partition:

parted /dev/sda mkpart primary ext4 22GB 100%
mkfs.ext4 /dev/sda2

This creates and formats a new ext4 partition.

Step 3 - Mountpoint Preparation

Prepare and mount the new partition:

mkdir /data
mount /dev/sda2 /data
df -h | grep data

Then check your partitions again, for example with:

lsblk

If this look good, reboot the server to exit the Rescue System and boot normally.

After reboot, the /data directory might no longer be available. If it is missing, create it again.

Step 4 - Configure fstab

Check the UUID of the new partition:

blkid /dev/sda2

Save the UUID for the fstab configuration.

Edit /etc/fstab and add the following line:

Replace  with the UUID of /dev/sda2.
UUID=<uuid-data> /data ext4 defaults 0 2

Step 5 - Test the Setup

Reload systemd and remount all:

systemctl daemon-reload
mount -a

Verify with:

df -h

Reboot the server to ensure the configuration persists:

reboot
df -h

Conclusion:

The root partition (/) has been reduced to 20 GB.
A new data partition (/data) uses the remaining disk space.
Automatic mounting of /data is configured via fstab.