Back up error

[Drax]

I recently increased the backup drive from 2TB to 8TB. I restarted backups after the new drive was installed.
However the issue is now it seems that the backup is running beyond 24 hours. This lead to unexpected status the next time that the back was to run, ie the next night. The task started two days ago was aparently still running. I shut that task down but now the storage states 200GB used while there are only 120GB of backups showing. How do I reclaim the lost 80GB?

What could be wrong to cause this issue? The new drive is faster and has better speed than the old one. Atleast that's what their specs say. Ran a speed test on it and it's less than 1MBS! Should be 30MBS

 

[Drax]

BTW the Drives are external USB Seagate Backup Plus drives Seagate says that they don't test their drives in a linux environment. I checked WD and Hitachi, neither do they. So how do I select an external USB drive for backup? My system is quite small which is why we opted for USB drives as the overnight period everything is quiet.