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Date:      Mon, 22 Mar 2004 16:35:56 -0800
From:      Claus Assmann <freebsd+fs@esmtp.org>
To:        freebsd-fs@freebsd.org
Subject:   Re: softupdates and two different MTAs
Message-ID:  <20040323003556.GA22741@zardoc.esmtp.org>
In-Reply-To: <20040319221643.GA90277@dan.emsphone.com>
References:  <20040317060617.GA23526@zardoc.esmtp.org> <20040319221643.GA90277@dan.emsphone.com>

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On Fri, Mar 19, 2004, Dan Nelson wrote:
> In the last episode (Mar 16), Claus Assmann said:
> > | program       | FS               |  writes | reads |
> > |---------------+------------------+---------+-------|
> > | sm8.12.11     | UFS, softupdates |     236 |     0 |

> > | sm9.0.0.12    | UFS, softupdates |    3500 |     4 |

> So something is either not fsyncing, or there is clustering going on
> behind the scenes.  The sm8 softupdates count is disturbingly low, even
> assuming good clustering.

You are right, it is too low. After following your advice about
adding the disk I/O stats to sendmail 8 itself, I finally found
that the cf file had SuperSafe=m, which causes it to not issue most
of the fsync(2) calls. With SuperSafe=true sm8 uses about twice as
many disk writes as sm9 and hence the latter is about two times
faster than the former.

Thanks for your reply!



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