breakage? when using --ignore-times with --link-dest

[Wayne Davison]

On Thu, Aug 30, 2007 at 03:01:13PM -0400, Ray and Sandie Clark wrote:
> I am trying to use --ignore-times with --link-dest and find that all
> files are duplicated inappropriately (IMHO).

Rsync only hard-links a file with its --list-dest version if it is not
transferred.  Using --ignore-times causes all files to be transferred,
so a --link-dest hierarchy only supplies file data for a more efficient
transfer (assuming the transfer is remote) when combined with -I.

> If --ignore-times is not specified, only mtime and the file size is
> checked so rsync doesn't notice that other inode information changed
> (ctime and links).

You want the --checksum option.  If you want rsync to hard-link together
files with differing attributes (such as differing mtime), that
attribute must not be specified as preserved (e.g. --no-times) OR you
could have rsync copy into a hierarchy of files instead of an empty
hierarchy as an alternate means of treating the history of file
attributes as unimportant.

One way to speed up the --checksum option is a preliminary patch named
check checksum-updating.diff in the patches dir.  It's purpose is to
maintain .rsyncsum files in the source based on extra file data, such
as ctime and (coming soon) inode.  When this is done right, it will
allow a new kind of transfer check that is not as expensive full-file
checksumming and not as fragile as only monitoring size and mtime.

..wayne..