/dev/mapper/ubuntu--vg-root is full

Solution 1:

/dev/mapper indicates that you're using LVM; so resizing the physical volume is not enough to resize the logical volume contained within, let alone the filesystem.

To increase the filesystem size, I followed these instructions from ServerFault with success:

1. First, I increased the physical partition using gparted. This was straightforward, and I assume you've already done that. If you don't have access to a LiveCD, you can increase the size of the physical disk while online, via pvresize, as shown in the linked instructions.

2. Then I used lvresize to grow the logical volume to fill the physical volume. I used pvdisplay to verify the size of the physical volume, and tried using that size.

    sudo lvresize -L 28.82G /dev/ubuntu-tt-vg/root
   

However, it was too large, so I started with 27G, and kept resizing my partition bigger until I hit the max.

3. Then, I used resize2fs to grow the filesystem inside the logical volume.

    sudo resize2fs /dev/ubuntu-tt-vg/root 7290881
   

Finding the max here was much easier. If you try a number bigger than the max, it will tell you exactly what the max is.

4. At this point, df -h should show that your filesystem has grown to the new size.