How can I resize an ext root partition at runtime?

gparted is the best available tool for this; it will automatically convert a request for resizing into the requisite FS-shrink, partition-shrink, move, ...

It is possible to do a on-line resize of a ext4 filesystem, even if it's your root partition. Use the resize2fs command. sudo resize2fs /dev/ ...

You need to first increase the size of the partition, and then the size of the file system in it. I find resizing partitions easiest with cfdisk.

Right click on the / partition and Resize/Move. Change the values there to allocate more space.

You're working on an XFS filesystem, in this case you need to use xfs_growfs instead of resize2fs. Two commands are needed to perform this task.

Learn the step by step process of how to resize a standard partition In Linux without unmounting a filesystem and without downtime.

My idea was to enlarge sda3 in the Partition Table (not the FS) and then use resize2fs to online resize it.

You can resize your root partition “live”. Assuming your drive has been already resized on the hypervisor side (eg from 20GB to 40GB), you need to follow the ...

The following is a guide to resizing your root ext4 file system online. After the operation, your partition will have more free space.

First, add the space to your system, whether that be inserting physical drives, allocating disk space in a pool for your VM, or just editing the configuration ...