Subject: Re: DEV_B_SIZE
To: Julian Elischer <julian@elischer.org>
From: None <phk@freebsd.org>
List: tech-kern
Date: 01/31/2003 20:58:27
In message <Pine.BSF.4.21.0301311144370.45015-100000@InterJet.elischer.org>, Ju
lian Elischer writes:
>
>
>One thign I thought of is that it is not uncommon to 'dd' an entire
>filesystem from one partition to another.
>If we create a filesystem that is 'aligned' and we copy it to be
>'unalligned', we'd have a sudden performance drop for no immediatly
>obvious reason. What was one write, would become a 2-sector read,
>modify and 2-sector write. Especially when copying from one failing
>drive to another with slightly different characteristics.
If you run dd without bs=ALOT you deserve bad throughput.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
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