Date: Wed, 02 Aug 2006 13:59:40 -0700 From: Julian Elischer <julian@elischer.org> To: freebsd-hackers@freebsd.org Subject: Re: [PATCH] adding two new options to 'cp' Message-ID: <44D1123C.6080601@elischer.org> In-Reply-To: <200608021746.k72HkIRO004011@lurza.secnetix.de> References: <200608021746.k72HkIRO004011@lurza.secnetix.de>
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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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