Re: [PATCH] adding two new options to 'cp'

Oliver Fromme wrote:

Bakul Shah wrote:
> Peter Jeremy wrote:
> > As a general comment (not addressed to Tim): There _is_ a downside
> > to sparsifying files. If you take a sparse file and start filling
> > in the holes, the net result will be very badly fragmented and hence
> > have very poor sequential I/O performance. If you're never going to
> > update a file then making it sparse makes sense, if you will be
> > updating it, you will get better performance by making it non-sparse.
> > Except for database tables how common is this?

For example image files of media, e.g. ISO9660 images
or images of hard disk partitions. I often have to handle
such images, and I certainly do _not_ want them to be
sparse.



well then you'd be silly to go to the extra work fo specifying --sparse
(or whatever) wouldn't you?

Before someone adds a bogus "sparse file support" option
to cp(1), I would rather prefer that someone fixes the
existing -R option which currently doesn't handle hard-
links correctly.



It never worked as you suppose. Changing it would be a surprise
(though to me a pleasant one) to many.

That flaw is documented in the manual page, so it might
not count as a "bug", but it's a flaw nevertheless. A lot
of people -- even so-called professional admins -- use
"cp -Rp" to copy directory hierarchies, and afterwards
they wonder why the copy takes up much more space than
the original, because all hardlinks have been copied as
separate files (if they notice at all).



I ALWAYS use find . -depth -print0|cpio -pdmuv0 {dest}
or -pdlmuv (poodle-move-0?) if I want links from old to new. because it
is guaranteed to do that but cp is not.

Oh by the way: Linux' option for sparse file handling
is "--sparse", and there is no one-letter option (both
-s and -S exist, but have nothing to do with sparse
files). So there wouldn't be an easy way for FreeBSD to
stay compatible with Linux.

Best regards
Oliver



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