Re: Removing softdep

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sat, Jun 07, 2008 at 10:31:52AM +0300, Jukka Marin wrote:
> On Fri, Jun 06, 2008 at 08:17:15PM -0400, Jared D. McNeill wrote:
> > Seconded. To achieve the same performance as I have today with softdeps, 
> > it is crucial that I must be able to switch to journaled ffs without hassle.
> 
> Will the journaled fs give us the same performance as softdeps?  Does
> journalling improve read performance?
> 
> I have been using softdeps with success for meny years on every machine I
> have.  Without softdeps, disk performance suffers when accessing lots of
> small files (like when building software).  

softdeps improves write performances of metadata. A metadata-journalled 
FS should give about the same win (and probably better in some workload,
as softdep cause access to stall completely when it flushes its queue in
some cases). AFAIK softeps doesn't help in any way for reads.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--