How to extend an ext4 partition and filesystem?

I have a 400GB disk with a 320GB ext4 partition. I would like to grow the ext4 partition to use the left space (80GB of free space).

+--------------------------------+--------+
|             ext4               |  Free  |
+--------------------------------+--------+

How could I do this?

I've seen people using resize2fs but I don't understand if it resizes the partition.

Another solution would be to use fdisk but I don't want to delete my partition and loose data. How could I simply grow the partition without loosing any file?

Note: I'm talking about an un-mounted data partition without LVM and I have backups, but I'd like to avoid spending some time on recovery.

You must begin with the partition unmounted. If you can't unmount it (e.g. it's your root partition or something else the system needs to run), use something like System Rescue CD instead.

1. Run parted, or gparted if you prefer a GUI, and resize the partition to use the extra space. I prefer gparted as it gives you a nice graphical representation, very similar to the one you've drawn in your question.

2. resize2fs /dev/whatever

3. e2fsck /dev/whatever (just to find out whether you are on the safe side)

4. Remount your partition.

While I've never seen this fail, do back up your data first!

Yes, you can grow EXT4 fs online if you have partition already sorted. Have you got partition sorted? Have you got LVM?

sudo resize2fs /dev/drive_to_grow

fdisk will resize your partition, true, but if this a root partition (or if fact any mounted partition) it will have to be unmounted first. So offline most likely!

As with anything related to disk/fs operations I strongly recommend to have backup, and tested, well understood, recovery process.

Note, on some VDS servers you could have non-primary root partition and need to resize Extended partition container first

For example, you've just upgraded your plan and have something like:

Disk /dev/vda: 83886080s
Number  Start    End        Size       Type      File system  Flags
1      2048s    194559s    192512s    primary   ext2         boot
2      196606s  51197951s  51001346s  extended
5      196608s  51197951s  51001344s  logical   ext4

Here /dev/vda2 - is your Extended container. And /dev/vda5 - main partition that we need to resize to full available space.

The simpliest way:

apt-get -y install parted
parted /dev/vda unit s print all # print current data for a case
parted /dev/vda resizepart 2 yes -- -1s # resize /dev/vda2 first
parted /dev/vda resizepart 5 yes -- -1s # resize /dev/vda5
partprobe /dev/vda # re-read partition table
resize2fs /dev/vda5 # get your space