Rdiff-backup
From DWIKI
Really, just avoid using it.
FAQ
revious backup seems to have failed, regressing destination now
Warning, could not find mirror_metadata file. Metadata will be read from filesystem instead. Fatal Error: No metadata for time Sun Apr 15 23:31:06 2018 (1523835066) found, cannot regress
https://lists.gnu.org/archive/html/rdiff-backup-users/2003-07/msg00080.html
