[Mailman-Developers] Problem with MM after power outage

Peter C. Norton spacey-mailman at lenin.nu
Mon Sep 15 14:50:33 EDT 2003


On Fri, Sep 12, 2003 at 05:56:00PM -0400, Barry Warsaw wrote:
> On Fri, 2003-09-12 at 17:40, Harald Meland wrote:
> > Hence, I think it makes more sense to have the default be "do
> > fsync(2)", and let any performance-conscious site decide whether it
> > wants to explicitly value performance over safety.
> 
> Except that when I did some very simple tests, I saw a 97% hit in
> performance with fsync turned on.  This on a RH9, ext3 Linux box of the
> Dell Optiplex variety.  That makes me very nervous to add in a patch
> release that won't have any beta testing.  I've also never seen the bug
> on python.org, which may or may not be representative of the world at
> large.

Wow.  97%?  That's way too high.  I'd expect about 50% at worst - for
the extra sync to disk when it enters mailman's queue and one more to
flush the message when its made it though the outbound queue to the
MTA.  This is just a question, because I still don't know much about
the mm 2.1 internals, but is there a chance you're sync()'ing more
often then you need?
 
> I'm happy to re-address this for the next major release, but for 2.1.3 I
> don't want to enable fsync by default, and I definitely don't want to do
> any probing/guessing of filesystems, etc.

That makes sense to me.

-Peter

-- 
The 5 year plan:
In five years we'll make up another plan.
Or just re-use this one.




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