macOS and Time Machine backup
After weeks of problems with Time Machine - eg the calculation of the duration of a backup of just 1 Gb must be interrupted after three days - including an incident ticket at Apple which was not able to solve the issue (btw: Thank you for your help, time and assistance, even when you not found the root cause).
Each time when we attached a disk device to initiate a backup it starts to calculate the time and never came to an end. Today we found the root cause for this behavior:
An application (Disk Drill) created a subdirectory on the harddrive and created a very huge number of small files in that directory. We analyzed this using
sudo fs_usage -w |grep -i backupd |grep -i fsctl
and recognized that a lot of files located in
where responsible for this misbehaviour. Excluding this directory from Time Machine solves the issue. Thanks to Mac O' Clock for the hints to solve this issue.