Well, i'm confused, something is weird here.
Your fstab shows:
# Entry for /dev/sda1 :
UUID=fb88ff0f-7d89-4213-b23b-1b73a06ea64d / ext4 acl,relatime 1 1
ls -l /dev/disk/by-uuid/ shows
lrwxrwxrwx 1 root root 10 Mar 11 12:27 03d31702-f7cf-4fd5-aaca-7a5afc679f5e -> ../../sda1
MCC shows:
Mount point: /backup
Device: sda1
Volume label: backup
UUID: 03d31702-f7cf-4fd5-aaca-7a5afc679f5e
The problem is that sda1 is your root partition according to your fstab, but ls -l /dev/disk/by-uuid/ and MCC
show something different. Could you please show the output as root of
blkid and
mount?
Relating to changing the user or making it writeable for your user, there are many ways to do this.
You could allow your user to mount this, so you could mount it manually and it would belong to the user
who mounted it, or you could automatically mount it and specify a user who should be the owner of all
files, or you could make it writeable to everybody.
But first we need to clear up the confusion about your partitions.