[plug] tar vs cp -r

[Quintin Lette]

When I copied my Solaris Jumpstart installation source to my linux
server, the only way I used to successfully do it was

tar cfp /jumpstart - | ssh scorpion -C "( cd /jumpstart && tar xf - )"

however within linux itself, especially on the same system I have
never had problems with cp -a solaris, as with most unix variants,
does not have gnu cp and therefore the -a switch, thus you need to use
tar.

the p switch is for preserving links, the reason why my jumpstart
didn't work with cp -r over nfs. The - does the same standard out bit,
and standard out means you can copy over ssh etc. With Linux I would
just use standard cp -a which should be faster (your not copying to an
intermediate point) but I always use tar on Solaris and between
systems.

Cheers

Quintin

On Thu, 10 Mar 2005 17:51:03 +0800, Jim Householder
<nofixed at westnet.com.au> wrote:
> Craig Ringer wrote:
> > On Thu, 2005-03-10 at 14:51 +0800, Jim Householder wrote:
> >
> >>Hi
> >>
> >>On a number of occasions I have seen a preference shown for using tar to
> >>move large trees rather than cp -r.
> >
> >
> > In addition to the points made by others, tar works well over ssh (so
> > long as you use no-pty, as I found out) and can be *dramatically* faster
> > than using `scp -r'.
> >
> > It's also possible to pipe a list of files to be copied, generated by,
> > eg, `find', into tar (or at least star) or add restrictions like files
> > modified after a certain date. `cp -r' isn't really all that smart.
> >
> > For just straight copies, cp -aR should do the job nicely. More complex
> > tasks can benefit from using an archiver (like tar, star, pax, etc) or
> > special tool like rsync or unison.
> >
> > --
> > Craig Ringer
> 
> Thanks guys.  I'm copying distros (2.2, 3.2GB) from dvd to disk for a
> network install.  I've decided to use tar from /media/dvd:
>     tar cOv * | tar xC /distros/suse -
> 
> It seems to be working, but it's really stuffing the mouse around.
> *very* erratic movement with random click-and-drags, and very slow
> response.  top indicated some idle time but it seems like the system is
> seriously cpu-bound.
> 
> Jim
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