On Tue, Feb 25, 2014 at 10:53:07 +0100, Charles Stroom wrote: > I than repeated the whole sequence, with the "--atime-preserve=replace" > added, and there is no change: again "full" incremental backup. > > And than again but now with "--atime-preserve=system" and now this > works! >
Right. If you include "--atime-preserve=replace", tar actually has to explicitly set the atime back to its original value -- and in the process it changes the ctime for the file, thus triggering that file to be included in the next incremental dump... On the other hand, ""--atime-preserve=system" causes tar to tell the OS essentially to pretend that particular access never happened in the first place, and thus there's no need to go back and reset the atime later. (This topic is discussed on the File Attributes page of the tar manual: http://www.gnu.org/software/tar/manual/html_node/Attributes.html#SEC137 ) Note that it's an updated ctime that would cause the file to be included in the next level 1 dump. Changed atimes don't trigger the problem -- otherwise just looking at a file would cause it to get included in the next dump.... > Is there an easy way to get this option added to tar in amanda, or do I > need to recompile? I'm fairly certain that Amanda will never send "--atime-preserve=replace". You can find out what your version of amanda is using by searching for the the '/bin/tar...' line in the /var/log/amanda/client/[CONFIG]/amgtar.*.debug log files (or equivalent). (In my Amanda 2.6.1p1 installation, I see it's sending "--atime-preserve=system".) In any case, (as you've already realized later in the thread) in the case of actual Amanda runs, your always-full-sized-dumps problem is is probably not related to --atime-preserve. Nathan ---------------------------------------------------------------------------- Nathan Stratton Treadway - [email protected] - Mid-Atlantic region Ray Ontko & Co. - Software consulting services - http://www.ontko.com/ GPG Key: http://www.ontko.com/~nathanst/gpg_key.txt ID: 1023D/ECFB6239 Key fingerprint = 6AD8 485E 20B9 5C71 231C 0C32 15F3 ADCD ECFB 6239
