Hi Igor,
Thanks for your info, would I be correct to assume that resizing of the /dev/md5 partition wont affect Plesk.
My backup process process does complete, but when I click on the download icon I think Plesk tries to create one file inside the /dev/md5 partition which is only 5GB and my backup is 15GB.
Is there a command that I can run to combine the backup files into one file?