Backing up 1st time to new external 2gb hdd - Permission denied when trying to create ‘/duplicity-full.20190515T021430Z.vol1.difftar.gz’.

What happens if you try creating a file on that device using another program?

From the desktop File viewer in Ubuntu, I cannot do anything with "2TB Volume".
From cli, I can do this:
joe@joeslinux:~$ cd /media/sde1
joe@joeslinux:/media/sde1$ mkdir backup
mkdir: cannot create directory ‘backup’: Permission denied
joe@joeslinux:/media/sde1$ sudo mkdir backup
joe@joeslinux:/media/sde1$ ls -al
total 12
drwxr-xr-x 3 root root 4096 May 15 13:23 .
drwxr-xr-x 4 root root 4096 May 14 21:29 ..
drwxr-xr-x 2 root root 4096 May 15 13:23 backup
joe@joeslinux:/media/sde1$ cd backup
joe@joeslinux:/media/sde1/backup$ touch x
touch: cannot touch 'x': Permission denied
joe@joeslinux:/media/sde1/backup$ sudo touch x
joe@joeslinux:/media/sde1/backup$ ls -al
total 8
drwxr-xr-x 2 root root 4096 May 15 13:23 .
drwxr-xr-x 3 root root 4096 May 15 13:23 ..
-rw-r--r-- 1 root root 0 May 15 13:23 x
joe@joeslinux:/media/sde1/backup$

I have to use Sudo for everything.

What should I be entering in on Storage Location?
Currently, I have
storage location: 2TB Volume
Folder: nothing

I have also tried
storage location: Custom Location
folder: file:///media/sde1
and
storage location: Local Folder
folder: /media/sde1
in both of which cases, the "Back Up Now" button is greyed out

Also, don't know if this helps, but this is what I did right before to format the new 2TB disk.
cd /dev
ls s*
mount | grep sde1
fdisk -1
sudo fdisk -l
sudo fdisk /dev/sde
sudo mkfs.ext4 /dev/sde1
sudo mkdir /media/sde1
sudo mount /dev/sde1 /media/sde1
cd /media/sde1
ls -al

The default file protection settings on a new-formatted device are set such that only root can create files.
You have to modify the protection settings for the backup directory, that you can create files there (without sudo).

Try the following commands:

sudo chown joe /media/sde1/backup
sudo rm /media/sde1/backup/x
touch /media/sde1/backup/x

Thank you, that was a big help.
Now, I run into a new problem,
Deja Dup is telling me I do not have enough disk space

When I run command:
joe@joeslinux:~$ df -a
Filesystem 1K-blocks Used Available Use% Mounted on
sysfs 0 0 0 - /sys
proc 0 0 0 - /proc
udev 32879708 0 32879708 0% /dev
devpts 0 0 0 - /dev/pts
tmpfs 6588544 709196 5879348 11% /run
/dev/nvme0n1p1 180072840 16744344 154158272 10% /
securityfs 0 0 0 - /sys/kernel/security
tmpfs 32942716 78260 32864456 1% /dev/shm
tmpfs 5120 4 5116 1% /run/lock
tmpfs 32942716 0 32942716 0% /sys/fs/cgroup
cgroup 0 0 0 - /sys/fs/cgroup/systemd
pstore 0 0 0 - /sys/fs/pstore
cgroup 0 0 0 - /sys/fs/cgroup/cpu,cpuacct
cgroup 0 0 0 - /sys/fs/cgroup/devices
cgroup 0 0 0 - /sys/fs/cgroup/hugetlb
cgroup 0 0 0 - /sys/fs/cgroup/freezer
cgroup 0 0 0 - /sys/fs/cgroup/net_cls,net_prio
cgroup 0 0 0 - /sys/fs/cgroup/blkio
cgroup 0 0 0 - /sys/fs/cgroup/perf_event
cgroup 0 0 0 - /sys/fs/cgroup/memory
cgroup 0 0 0 - /sys/fs/cgroup/pids
cgroup 0 0 0 - /sys/fs/cgroup/rdma
cgroup 0 0 0 - /sys/fs/cgroup/cpuset
systemd-1 0 0 0 - /proc/sys/fs/binfmt_misc
debugfs 0 0 0 - /sys/kernel/debug
hugetlbfs 0 0 0 - /dev/hugepages
mqueue 0 0 0 - /dev/mqueue
tracefs - - - - /sys/kernel/debug/tracing
configfs 0 0 0 - /sys/kernel/config
fusectl 0 0 0 - /sys/fs/fuse/connections
/dev/loop3 144128 144128 0 100% /snap/gnome-3-26-1604/74
/dev/loop0 55040 55040 0 100% /snap/core18/941
/dev/loop1 168960 168960 0 100% /snap/brave/59
/dev/loop4 93312 93312 0 100% /snap/core/6531
/dev/loop7 55040 55040 0 100% /snap/core18/782
/dev/loop5 108032 108032 0 100% /snap/shotcut/45
/dev/loop6 55040 55040 0 100% /snap/core18/731
/dev/loop8 144128 144128 0 100% /snap/gnome-3-26-1604/82
/dev/loop9 223360 223360 0 100% /snap/gimp/130
/dev/loop10 203008 203008 0 100% /snap/atom/226
/dev/loop11 36224 36224 0 100% /snap/gtk-common-themes/1198
/dev/loop13 159232 159232 0 100% /snap/brave/57
/dev/loop12 108032 108032 0 100% /snap/shotcut/43
/dev/loop14 173568 173568 0 100% /snap/gimp/113
/dev/loop15 144128 144128 0 100% /snap/gnome-3-26-1604/78
/dev/loop16 35712 35712 0 100% /snap/gtk-common-themes/1122
/dev/loop18 224256 224256 0 100% /snap/gimp/165
/dev/loop17 203008 203008 0 100% /snap/atom/225
/dev/loop19 114688 114688 0 100% /snap/shotcut/41
/dev/loop20 91392 91392 0 100% /snap/core/6673
/dev/loop21 161024 161024 0 100% /snap/brave/58
/dev/loop22 91648 91648 0 100% /snap/core/6818
/dev/loop23 35456 35456 0 100% /snap/gtk-common-themes/818
/dev/md0 1922481984 297535152 1527267324 17% /home
tmpfs 6588544 160 6588384 1% /run/user/1000
gvfsd-fuse 0 0 0 - /run/user/1000/gvfs
tmpfs 6588544 709196 5879348 11% /run/snapd/ns
nsfs 0 0 0 - /run/snapd/ns/gimp.mnt
jaxx-1.3.18-x86_64.AppImage 0 0 0 - /tmp/.mount_jaxx-1dCMYeD
nsfs 0 0 0 - /run/snapd/ns/brave.mnt
/dev/sde1 1922728840 68956 1824967824 1% /media/joe/82374f03-c484-4420-8693-6ed0a7704b4e
/dev/loop24 206464 206464 0 100% /snap/atom/227
joe@joeslinux:~$ ^C

md0 is what I am trying to back up. It is 4 X 1TB disks in Raid 10. Used space is 297,535,152 (297GB). I am backing up to sde1, with free space of 1,922,728,840 (1.9TB).

What are you trying to backup: md0 or /home ?
/dev/md0 is the whole disk including the free space, and /home is just the used space.

On Folders to save I have selected home(joe), this is my ~ folder.
Folders to ignore Trash and ~/Downloads.

Storage location is Local Folder
Folder is /media/sde1/backup

Do you still get an error message about not enough free space?
Can you provide the full text of that message?

Backup Failed

Backup location is too small. Try using one with
more space.

No. No. It's not too small. As from the detail in my post on 5/15, I am backing up to sde1, a 2TB hard disk, that's 1,922,728,840 byte of free and usable space. The entire content of what I am backing up is /home/joe on md0, which stores no greater than 0.28TB, 297,535,152 bytes. It fits, with plenty left over.

I wouldn't be keeping this chain open so long if the answer were that simple.

This question was expired because it remained in the 'Open' state without activity for the last 15 days.