dd issues

[Jim Stapleton]

On 5/1/06, Greg 'groggy' Lehey <grog at freebsd.org> wrote:
> On Monday,  1 May 2006 at 19:44:00 -0400, Jim Stapleton wrote:
> > I'm trying to back up some of my software, and I'm having some
> > problems, I found something in the archives specifying the need to set
> > a block size of 2k or greater. This makes a backup (I've not tested it
> > yet).
> >
> > My questions are:
> > (1) Why does this work?
>
> Why shouldn't it?

Because the alternative does not work (default block size, block size
less than 2k).

>
> > (2) Is it possible that not using the default/found block size will
> > cause issues?
>
> Yes.
>
> Without more background in what you're trying to do (you don't even
> say what backup program or what medium you're trying to back up to),
> or what your concerns are, it's difficult to answer this question.
> There are no specific issues with block size on most archivers, but in
> general large block sizes (64 kB or larger) will give better
> performance.

program is dd, source medium is CD, destination medium is hard drive.
Possible later medium is compressed files on HD DVD-RW