From: Stephan von Krawczynski <skraw@ithnet.com>
To: John Bradford <john@grabjohn.com>
Cc: josh@stack.nl, alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org
Subject: Re: Are linux-fs's drive-fault-tolerant by concept?
Date: Sun, 20 Apr 2003 19:01:19 +0200 [thread overview]
Message-ID: <20030420190119.048d3a43.skraw@ithnet.com> (raw)
In-Reply-To: <200304201640.h3KGeTs6000657@81-2-122-30.bradfords.org.uk>
On Sun, 20 Apr 2003 17:40:29 +0100 (BST)
John Bradford <john@grabjohn.com> wrote:
> > > Fault tolerance in a filesystem layer means in practical terms
> > > that you are guessing what a filesystem should look like, for the
> > > disk doesn't answer that question anymore. IMHO you don't want
> > > that to be done automagically, for it might go right sometimes,
> > > but also might trash everything on RW filesystems.
> >
> > Let me clarify again: I don't want fancy stuff inside the filesystem that
> > magically knows something about right-or-wrong. The only _very small_
> > enhancement I would like to see is: driver tells fs there is an error while
> > writing a certain block => fs tries writing the same data onto another
> > block. That's it, no magic, no RAID stuff. Very simple.
>
> That doesn't belong in the filesystem.
>
> Imagine you have ten blocks free, and you allocate data to all of them
> in the filesystem. The write goes to cache, and succeeds.
>
> 30 seconds later, the write cache is flushed, and an error is reported
> back from the device.
And where's the problem?
Your case:
Immediate failure. Disk error.
My case:
Immediate failure. Disk error (no space left for replacement)
There's no difference.
Thing is: If there are 11 blocks free and not ten, then you fail and I succeed
(if there's one bad block). You loose data, I don't.
Regards,
Stephan
next prev parent reply other threads:[~2003-04-20 16:49 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-19 16:04 Are linux-fs's drive-fault-tolerant by concept? Stephan von Krawczynski
2003-04-19 15:29 ` Alan Cox
2003-04-19 17:00 ` Stephan von Krawczynski
2003-04-19 22:04 ` Alan Cox
2003-04-20 16:24 ` Stephan von Krawczynski
2003-04-20 13:59 ` John Bradford
2003-04-20 16:55 ` Stephan von Krawczynski
2003-04-20 17:12 ` John Bradford
2003-04-20 17:21 ` Stephan von Krawczynski
2003-04-20 18:48 ` Alan Cox
2003-04-20 20:00 ` John Bradford
2003-04-21 1:51 ` jw schultz
2003-04-19 21:13 ` Jos Hulzink
2003-04-20 16:07 ` Stephan von Krawczynski
2003-04-20 16:40 ` John Bradford
2003-04-20 17:01 ` Stephan von Krawczynski [this message]
2003-04-20 17:20 ` John Bradford
2003-04-21 9:32 ` Stephan von Krawczynski
2003-04-21 9:55 ` John Bradford
2003-04-21 11:24 ` Stephan von Krawczynski
2003-04-21 11:50 ` Alan Cox
2003-04-21 12:14 ` John Bradford
2003-04-19 16:22 ` John Bradford
2003-04-19 16:36 ` Russell King
2003-04-19 16:45 ` John Bradford
2003-04-19 16:52 ` Stephan von Krawczynski
2003-04-19 20:04 ` John Bradford
2003-04-19 20:33 ` Andreas Dilger
2003-04-21 9:25 ` Denis Vlasenko
2003-04-21 9:42 ` John Bradford
2003-04-21 10:25 ` Stephan von Krawczynski
2003-04-21 10:50 ` John Bradford
2003-04-19 20:38 ` Stephan von Krawczynski
2003-04-20 14:21 ` John Bradford
2003-04-21 9:09 ` Denis Vlasenko
2003-04-21 9:35 ` John Bradford
2003-04-21 11:03 ` Stephan von Krawczynski
2003-04-21 12:04 ` John Bradford
2003-04-21 11:22 ` Denis Vlasenko
2003-04-21 11:46 ` Stephan von Krawczynski
2003-04-21 12:13 ` John Bradford
2003-04-19 20:05 ` John Bradford
2003-04-19 23:13 ` Arnaldo Carvalho de Melo
2003-04-19 17:54 ` Felipe Alfaro Solana
2003-04-25 0:07 ` Stewart Smith
2003-04-25 0:52 ` Richard B. Johnson
2003-04-25 7:13 ` John Bradford
[not found] ` <20030419161011$0136@gated-at.bofh.it>
2003-04-19 17:18 ` Florian Weimer
2003-04-19 18:07 ` Stephan von Krawczynski
2003-04-19 18:41 ` Dr. David Alan Gilbert
2003-04-19 20:56 ` Helge Hafting
2003-04-19 21:15 ` Valdis.Kletnieks
2003-04-20 10:51 ` Helge Hafting
2003-04-20 19:04 ` Valdis.Kletnieks
2003-04-19 21:57 ` Alan Cox
2003-04-20 10:09 ` Geert Uytterhoeven
2003-04-21 8:37 ` Denis Vlasenko
2003-05-05 12:38 ` Pavel Machek
2003-04-19 22:02 ` Alan Cox
2003-04-20 8:41 ` Arjan van de Ven
2003-04-25 0:11 ` Stewart Smith
2003-04-20 15:06 Chuck Ebbert
2003-04-20 15:19 ` John Bradford
2003-04-20 17:03 Chuck Ebbert
2003-04-20 17:25 ` John Bradford
2003-04-20 17:28 Chuck Ebbert
2003-04-21 9:36 ` Stephan von Krawczynski
2003-04-20 17:28 Chuck Ebbert
2003-04-20 17:44 Chuck Ebbert
2003-04-20 17:44 Chuck Ebbert
[not found] <mail.linux.kernel/20030420185512.763df745.skraw@ithnet.com>
[not found] ` <03Apr21.020150edt.41463@gpu.utcc.utoronto.ca>
2003-04-21 11:19 ` Stephan von Krawczynski
2003-04-21 11:52 ` Alan Cox
2003-04-21 14:14 ` Valdis.Kletnieks
2003-05-06 7:03 ` Mike Fedyk
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