Subject: Re: soft updates Re: Summer of code ideas
To: Bill Stouder-Studenmund <wrstuden@netbsd.org>
From: Dieter <netbsd@sopwith.solgatos.com>
List: netbsd-users
Date: 04/06/2007 15:00:01
> > > Then for the real test start over and do it all again, but this time
> > > after "systat bufcache" shows that most of available RAM is used up
> > > for metadata an file data, pull the power plugs.  Then try to clean
> > > up the mess.
> >
> > What mess?  My understanding is that with soft updates, the only
> > thing that can possibly happen is that disk space can be lost.
> > The background fsck is for reclaiming this lost space.
> 
> That's both the idea and the promise. For better or worse, that has not=20
> been the experience of a number of users.

Did these users have their disk's write caches set to write-through
mode rather than write-back mode?  NetBSD doesn't do this by default,
you have to add code to /etc/rc.local.