Re: LFS support ?

[eric jackson <shinobi@monkey.org>]

On Sun, 3 Sep 2000, Rakhesh Sasidharan wrote:

> > 
> > No, OpenBSD does not support it currently as it really isn't much of a
> > useful fs. But I plan to have support for it back in the tree sometime,
> > probobly not before 2.8. It died because its uselessness and the fact
> > nobody used it. FreeBSD just completely stripped it from its tree, ours
> > just got stale.
> > 
> 
> In case you don't mind, could you elaborate a bit more:  I don't know much
> abt the technical details, but I found the concept of LFS very
> interesting (I had read up some articles that I got from the NetBSD
> page).  I thought it must be a very useful fs to have.  Why then do you
> say that it is not a very useful fs, and that it died out because of its
> uselessness ?  
> 

I say that because that is exactly what has happened. The reason for LFS
was for speed, to cut down on read/write calls by having 1 logical file
that was basically just appended too. In theory this sounds good, but it
didn't pan out. Why? basically because of the need for the cleaner to be
present to reclaim inodes, etc. This cleaner must be run in userland
because if put in kernel space it would be just too big, therefore slowing
it down more. A paper was presented at one conference (usenix?) explaining
exactly why LFS failed bad. Basically what works for speed is
ffs+softupdates and journaled filesystems.

Why NetBSD decided to revive LFS i dont know. Maybe for the same reasons i
decided to port that work and probobly expand as well. Because im
interesed in filesystems. Or maybe they think they can work some of the
kinks out making it a successful fs. I dont think that will happen
however.

				eric


> Rakhesh
> 
>