Re: Removing softdep

[David Holland <dholland-tech%netbsd.org@localhost>]

On Sat, Jun 14, 2008 at 06:09:08PM +0300, M.K. wrote:
 > > I also would like to see LFS fixed.
 > That makes two of us :)
 > 
 > > http://en.wikipedia.org/wiki/Log-structured_File_System_(BSD)
 > I've read that, but I've never investigated the internals of either FFS or
 > LFS. What I don't understand is the difference between journalling and
 > log-structured filesystems. Isn't log-structuring just a special case of
 > journalling?

In a sense, yes.

Suppose you took a journaling file system, and set it to journal data
as well as metadata. Then suppose you changed it around so reads could
be handled straight from the journal. Then you don't need anything
*but* the journal and you can use the whole disk for the journal.

That's essentially a log-structured file system.

-- 
David A. Holland
dholland%netbsd.org@localhost