Q:

rsync is filling up my root folder

I have been using rsync to back up my home folder to another internal disk drive.  The backups appear to be working fine.  The files and folder structure are being reproduced accurately on the backup drive.
I have, however, today received an error saying file not copied due to lack of space and a notification saying that the root folder has 0 bytes left.
The backup disk is a 2 TB disc and has plenty of space but the root folder is indeed full.  It appears that rsync has been making a backup copy of my home folder in /media in my root partition as well as on the backup drive.
The command I have been using is
rsync -auhv --delete --exclude 'Archives' /home/phill /media/phill/Backups
It appears that the destination part of the command
/media/phill/Backups 
has caused rsync to make a backup in the root /media folder and on the other drive simultaneously.  I’d be grateful if someone could tell me how to make the command point to the other internal backup drive only.
The backup drive would be sda1.  My Linux installation is on sdb1 in a 100 GB partition. I have a separate home folder in sdb3. I am running Ubuntu 18.04.4 LTS
The output from df -h is as follows
phill@Phill-PC:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on  
udev            7.8G     0  7.8G   0% /dev  
tmpfs           1.6G  2.3M  1.6G   1% /run  
/dev/sdb1        92G   46G   42G  53% /  
tmpfs           7.8G  138M  7.7G   2% /dev/shm  
tmpfs           5.0M  4.0K  5.0M   1% /run/lock  
tmpfs           7.8G     0  7.8G   0% /sys/fs/cgroup  
/dev/loop1       55M   55M     0 100% /snap/core18/1066  
/dev/loop2       15M   15M     0 100% /snap/gnome-characters/296  
/dev/loop0       43M   43M     0 100% /snap/gtk-common-themes/1313  
/dev/loop4      4.2M  4.2M     0 100% /snap/gnome-calculator/406  
/dev/loop3       94M   94M     0 100% /snap/core/9066  
/dev/loop5      256M  256M     0 100% /snap/gnome-3-34-1804/33  
/dev/loop7      161M  161M     0 100% /snap/gnome-3-28-1804/116  
/dev/loop10     3.8M  3.8M     0 100% /snap/gnome-system-monitor/100  
/dev/loop6      1.0M  1.0M     0 100% /snap/gnome-logs/100  
/dev/loop8      2.5M  2.5M     0 100% /snap/gnome-calculator/748  
/dev/loop12      63M   63M     0 100% /snap/gtk-common-themes/1506  
/dev/loop9      2.3M  2.3M     0 100% /snap/gnome-system-monitor/145  
/dev/loop11     150M  150M     0 100% /snap/gnome-3-28-1804/67  
/dev/loop13     1.0M  1.0M     0 100% /snap/gnome-logs/61  
/dev/loop14      89M   89M     0 100% /snap/core/7270  
/dev/loop15     384K  384K     0 100% /snap/gnome-characters/539  
/dev/loop16      55M   55M     0 100% /snap/core18/1754  
/dev/sdb3       1.7T  652G  914G  42% /home  
tmpfs           1.6G   16K  1.6G   1% /run/user/121  
tmpfs           1.6G   48K  1.6G   1% /run/user/1000  
/dev/sdc1       1.9G   32M  1.7G   2% /media/phill/PNY  
/dev/sdd1       3.8G   20M  3.8G   1% /media/phill/4GB  
/dev/sda1       1.8T  153G  1.6T   9% /media/phill/Backups1  

A:

This is part of my rsync backup bash file. I have had it fill / when not correctly mounted, so I had to add this:
my_mount="/mnt/backup"
# /dev/sdb4 backup_b partition on Z170, became sda4 with new NVMe drive
if grep -qs "$my_mount" /proc/mounts; then
  echo "It's mounted."
else
  echo "It's not mounted. Trying mount"
  mount -t ext4 /dev/sda4 $my_mount
  if [ $? -eq 0 ]; then
   echo "Mount success!"
  else
   echo "Something went wrong with the mount..."
   exit $?
  fi
fi

I have a lot of excludes, so use a file.
Backup your home directory with rsync and skip useless folders & 
What files and directories can be excluded from a backup of the home directory?

