On Tue, Jan 23, 2024 at 4:03 PM Thomas Schmitt <scdbac...@gmx.net> wrote: > > About timestamps and incremental backup: > > If you only go for mtime, them you miss changes of file attributes > which are indicated by ctime. > Even more, timestamps alone are not a reliable way to determine which > files are new at their current location in the directory tree. > If you move a file from one directory to the other, then the timestamps > of the file do _not_ get updated. Only the two involved directories get > new timestamps. > So when the backup tool encounters directories with young timestamps > it has to use other means to determine whether their data files were > moved. scdbackup uses recorded device and inode numbers, and as last > resort recorded MD5 sums for that purpose. > > (Of course, content MD5 comparison is slow and causes high disk load, > compared to simple directory tree traversal with timestamps and inode > numbers. So scdbackup tries to avoid this when possible and allowed > by the -changetest_options in the backup configuration file.) > > > Have a nice day :) > > Thomas >
This is one thing I enjoy with btrfs. It knows exactly every little thing that changed to your files since last time you backed it up, without having to scan everything. Even if you manually try to fake the datestamps etc. Finding that information is more or less instant, making backups easy.
