I am trying to --dry-run a backup to see if my exclusions work as expected. There are maybe 500.000 files with 5TB in total. The dry run takes 10 (!) hours to finish. Is this normal?
Exact time depends on your exact environment but for 5TB/500k files 10h is reasonable time - it is 140 MB/sec and many files is always PITA… So IMO it is good result.
An initial backup has to read in all files, depending where this is stored (I/O),processor capabilities and RAM etc. this can take a while. Subsequent backups will be speedier.
A backup dry-run currently behaves like a normal backup, except that is does not store any data. That means that all files still have to be fully processed.