In regard to: Re: [Networker] any tips for backing up enormous sparse...:

And meanwhile, just around the corner on the Internet, the o/s
developers are talking about much the same issue, but they are in the
position to do something about it...

It's about zfs... but it refers to solaris ufs having no special
handling for sparse files... and suggests other o/s's need something
added too...

http://blogs.sun.com/roller/page/bonwick?entry=seek_hole_and_seek_data

Thanks again for the research you've shared on this issue.  That link
was very useful.

I also turned up a couple links where other people have brought up the
same issue I did -- even if your backup software handles sparse files
correctly, reading something this size sequentially takes a long time.

I found an issue in Red Hat's bugzilla related to rsync taking a long
time to read /var/log/lastlog:

        https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=156809

and that report included a URL for a thread on the Fedora test list about
the same issue:

 https://www.redhat.com/archives/fedora-test-list/2005-June/thread.html#00308


In the end, Jeff Bonwick's blog entry summarized the issue best.
Hopefully some day most filesystems will have an interface like this,
and backup software will actually use that interface if it's present.

Until then, I think we're going to end up skipping /var/log/lastlog, and
dumping the text info to some other file that does get backed up.

Thanks for everyone's input on this.  It's been very useful.

Tim
--
Tim Mooney                              mooney AT dogbert.cc.ndsu.NoDak DOT edu
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