[Swift-devel] discussion for swift output file path

[Mihael Hategan]

On Thu, 2008-11-13 at 12:40 -0600, Zhao Zhang wrote:
> 
> Ben Clifford wrote:
> > On Thu, 6 Nov 2008, Zhao Zhang wrote:
> >
> >   
> >> I am working on integrate the Collective IO system and swift on BGP. Before
> >> that, for the purpose of put swift into production work,
> >>     
> >
> > It would be useful if the changes, if they're useful, end up in the 
> > production Swift SVN - keeping everyone's codebase fairly tightly 
> > converged seems a good thing to me.
> >
> > Points 1 and 3 below seem more difficult, but point 2:
> >
> >   
> >> 2. change wrapper.sh: copy files from local ramdisck to GPFS using dd           
> >> instead of cp,      straghtforward.                     
> >>     
> >
> > is easy to put in. Is there a measurable performance increase using dd 
> > rather than cp? And dd using default block size or different ones?
> >   
> yep, I made this working on surveyor. cp on CN uses a lined-buffer for 
> output, thus a bad performance.

Have you tried --sparse=never?