ufs+softupdates / consistency

[Arne Wörner]

--- Zhihui Zhang <zzhang at cs.binghamton.edu> wrote:
> On Wed, 26 Jan 2005, Arne Wörner wrote:
> > I would be glad, if somebody explains me, why ext2fs/async in
> > Linux kernel 2.4.27 (KNOPPIX V3.7) is much faster (about 4
> > times faster) than a ufs with soft updates on the same slice
of
> > the hard disc?
> > 
> > Is it due to consistency reasons? In case of a ext2fs/sync in
> > my Linux setting Linux was about 4 times slower.
> > 
> > Are we already trying to issue write order requests for the
> > disc blocks (whose write order is arbitrary) sorted by sector
> > number (in order to move the disc heads as less as possible)?
> > The disc write cache could do that, but I disabled it in order
> > to decrease the probability of inconsistency.
> >
> No file system is super for ALL benchmarks.  Maybe you should
> say something about your application, its access pattern, file
> count, file sizes, read/write ratio, etc.
> 
Ok

Reading a special device (like /dev/ad0s2) in FreeBSD R5.3 is as
fast as in KNOPPIX.

But writing a single new file with big block size (32k-128k) and
1000 blocks is much different (depends on Linux/FBSD and
sync/async). And I do not know now, why that is so.

For further information see
  http://home.tiscali.de/cmdr_faako/
, if you want, please.

-Arne Wörner



		
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