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Date:      Tue, 2 Mar 1999 18:48:00 +0100
From:      Harold Gutch <logix@foobar.franken.de>
To:        Don Wilde <dwilde1@thuntek.net>, Konrad Heuer <kheuer@gwdu60.gwdg.de>
Cc:        freebsd-advocacy@FreeBSD.ORG
Subject:   Re: The Linux PR firestorm disaster (w.r.t. FreeBSD)
Message-ID:  <19990302184800.B4386@foobar.franken.de>
In-Reply-To: <36DC09E3.2F959909@thuntek.net>; from Don Wilde on Tue, Mar 02, 1999 at 07:55:15AM -0800
References:  <Pine.BSF.4.05.9903020901310.3311-100000@gwdu60.gwdg.de> <36DC09E3.2F959909@thuntek.net>

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On Tue, Mar 02, 1999 at 07:55:15AM -0800, Don Wilde wrote:
> FreeBSD uses synchronous writes of data, whereas Linux, by default, uses
> asynchronous writes. This means that Linux doesn't write immediately:
> your data is saved in RAM until the machine is less busy, and then it
> writes. If your machine dies, you've lost the data. FreeBSD makes sure
> your data is saved immediately, and it's so much more efficient that
> even with safer writing policies FreeBSD is faster.

I saw a posting by Martin Cracauer to a German BSD-newsgroup a
couple of days ago, which can be summed up to "normal synchronous
writes (the 'classic' FreeBSD thing) are slow, asynchronous
writes (what Linux does) are dangerous - softupdates are a little
slower than asynchronous writes, but ensure the reliability of
synchronous writes.

Is there some real good comparism of all the three, like in what
case you might lose data with each of the three possibilities
(according to that posting, there's a small chance of data-loss
with synchronous writes, so I guess that it's the same for
softupdates, too) and (rough) speed-comparisms of them ?

bye,
  Harold

-- 
<Shabby> Sleep is an abstinence syndrome wich occurs due to lack of caffein.
Wed Mar  4 04:53:33 CET 1998   #unix, ircnet


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