On Thu, Feb 03, 2000 at 09:32:36AM -0600, [EMAIL PROTECTED] wrote:
> Using softupdates under *BSD gives you the reliability
> of sync (somewhat more, actually), with nearly the speed
> of async.
softupdates are supposed to help keep your filesystem in a
consistent state while providing asyncronous operation. When
qmail spools an email it assumes that it has been safely written
to disk. If you are using softupdates or an async filesystem the
file may still be in memory when the write call returns to qmail.
You will lose this message if you machine goes down at this time
but your whole filesystem won't be trashed.
AFAIK, the benefits of softupdates over fully asyncronous
operation has not been well proven. softupdates assure that the
metadata on the disk is always in a consistant state. It says
nothing about the data. In my past 7 years of using Linux I have
never seen an ext2 filesystem that fsck could not fix. Please
don't start this flamewar again though. Go to dejanews and
relive it in all its glory. :)
Getting back on topic, I use an ext2 async filesystem for qmail.
The tradeoff of performance for reliability is not worth it in my
opinion. The chances of my machines going down at the exact
moment that email could be lost seems pretty small. For high
volume sites with reliability requirements a journalling
filesystem like ext3 should probably be used.
Neil
