On Thu, Nov 29, 2001 at 08:12:26PM -0500, Greg A. Woods wrote:
> Since we are talking about softdeps here another good example is
> unlink(2).  If you've ever compared the time it takes to remove a large
> tree of large files with and without softdeps then you'll even further
> appreciate the benefits of delayed writes.  Sure they have to happen

Oh, I appreciate softdeps when unlinking. 

On my 1.5.2 Alpha with 64 megs of RAM a rm -rf of a largish tree
(like /usr/src) will panic the system. The kernel runs out of 
memory in not too much time. On reboot the fsck will take multiple 
hours to remove all of the disconnected files.

If I /bin/sync in the middle of the rm -rf a few times then the
kernel does not run out of memory and the panic is averted.

Incidentally, has anyone else seen this?
-- 
Kevin P. Neal                                http://www.pobox.com/~kpn/

"It sounded pretty good, but it's hard to tell how it will work out
in practice." -- Dennis Ritchie, ~1977, "Summary of a DEC 32-bit machine"