From owner-freebsd-questions  Thu Dec  6 16:11:31 2001
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Date: Thu, 6 Dec 2001 21:09:38 -0300 (ART)
From: Fernando Gleiser <fgleiser@cactus.fi.uba.ar>
To: BSD Freak <bsd-freak@mbox.com.au>
Cc: FreeBSD Questions <freebsd-questions@FreeBSD.ORG>
Subject: Re: Journaling File Systems and Soft Updates confusion
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On Fri, 7 Dec 2001, BSD Freak wrote:

> Hi all,

> The whole point of a journaling file system on systems such as
> Linux/NT/Solaris etc. is not to increase performance but rather to
> avoid an 'fsck' when the server gets shutdown "uncleanly". This is
> because fsck can take several hours to run on a very large filesystem.

In CURRENT, you can run fsck in background. Just wait until 5.0 is
out =0)

>
> FreeBSD's ffs curently cannot do this (avoid an fsck) with or without
> soft updates. Soft updates of FreeBSD is merely there to increase
> performance.

Nope. Soft Updates are a way to ensure file system consistency
after a crash.

>
> I may have this all wrong (someone please correct me if I have) but
> soft updates is NOT an equivalent to a journaling file system.

Go and read the paper by Seltzer, McKusik et al (see my earlier post)
comparing both. Then you'll know if you are wrong or not =0).



			Fer


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