[BBLISA] Live Sync / Backup / Sync without crawling

[Dean Anderson]

On Sat, 1 Nov 2008, Edward Ned Harvey wrote:

> Hey, anybody know of any program, which can sync or mirror a
> directory, without the need to scan the directory?  For now, I'd be
> happy to find *any* such program, for whatever OS.
> 
> I know it can be done, via things like inotify, FSEvents, or
> FindFirstChangeNotification ...
> 
> Take a really simple hypothetical example.  Suppose I want to rsync
> some dir to some foreign location periodically.  At present, every
> program I can find needs to crawl the local dir (or worse) to see
> what's changed.  But with inotify etc, it's possible to have already
> created a list of what's changed, and simply mirror the changes rather
> than doing the whole tree crawl.  This would be super useful for
> syncing a large directory.

Doesn't rsync allow you to give a list of files rather than a list of 
directories?

   --include-from=FILE  option looks like it should do the trick.

But it still has to scan the directory to find the listed files. If the
directory is large, this might be timeconsuming.  The only way around
that is to create hard links to the files you want to backup in another
directory, or find a way to split up your directory into smaller
directories.  Hardlinks require the inode to stay the same (a delete
followed by create with same name cannot be allowed as this results in a
different inode), but symlinks still have to go through the original
directory, so they are no help.

Hope that helps.

		--Dean


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