Re: File System Performance

[Xavier Bestel]

le lun 12-11-2001 à 23:39, Alan Cox a écrit :
> >         Corrections to speed-up the sizeing pass in Amanda:
> >         * tar.h: Declare dev_null_output.
> >         * buffer.c (open_archive): Detect when archive is /dev/null.
> >         (flush_write): Avoid writing to /dev/null.
> >         * create.c (dump_file): Do not open file if archive is being
> >         written to /dev/null, nor read file nor restore times.
> >         Reported by Greg Maples and Tor Lillqvist.
> > 
> > One wonders why.
> 
> So when you archive the file set twice (once to compute its size) its
> faster. Seems sane enough. 

What would have been sane is a tar --just-compute-the-size option, not
hardcoding /dev/null.