Date: Mon, 2 May 2005 16:07:42 +0200 (CEST) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-stable@FreeBSD.ORG Subject: Re: kernel: swap_pager: indefinite wait buffer - on 5.3-RELEASE-p5 Message-ID: <200505021407.j42E7gFv095417@lurza.secnetix.de> In-Reply-To: <42732577.9020100@geminix.org>
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Uwe Doering <gemini@geminix.org> wrote:
> Oliver Fromme wrote:
> > If they're really identical (i.e. the same size and same
> > geometry), then you can use dd(1) for duplication, like
> > this:
> >
> > # dd if=/dev/ad0 of=/dev/ad1 bs=64k conv=noerror,sync
> >
> > The "noerror,sync" part is important so the dd command will
> > not stop when it hits any bad spots on the source drive and
> > instead will fill the blocks with zeroes on the destination
> > drive. Since it's only the swap partition, you shouldn't
> > lose any data.
>
> I would like to point out that the conclusion you're drawing in the last
> sentence is invalid IMHO.
I'm afraid I don't agree.
> "indefinite wait buffer" messages at
> apparently random block numbers just indicate that the pager was unable
> to access the swap area (in its entirety!) when it wanted to. It means
> that the disk drive was either dead at that point in time or busy trying
> to deal with a bad sector.
>
> This sector could have been anywhere on the disk. It just kept the disk
> drive busy for long enough that the pager started to complain.
The OP specifically said that the swap_pager messages were
the only kernel messages that he got. That indicates that
only the swap partition is affected, because otherwise
there would have been other kernel messages indicating
I/O errors from one of the filesystems on that disk.
Best regards
Oliver
--
Oliver Fromme, secnetix GmbH & Co KG, Oettingenstr. 2, 80538 München
Any opinions expressed in this message may be personal to the author
and may not necessarily reflect the opinions of secnetix in any way.
"C++ is to C as Lung Cancer is to Lung."
-- Thomas Funke
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