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To: "Max Clark" <max.clark@media.net>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Tue, 02 Sep 2003 13:14:58 PDT."
             <ILENIMHFIPIBHJLCDEHKEEMIDCAA.max.clark@media.net> 
Date: Tue, 02 Sep 2003 22:12:30 +0200
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cc: freebsd-hackers@freebsd.org
cc: freebsd-performance@freebsd.org
cc: freebsd-questions@freebsd.org
Subject: Re: FW: 20TB Storage System 
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In message <ILENIMHFIPIBHJLCDEHKEEMIDCAA.max.clark@media.net>, "Max Clark" writ
es:
>I know adding ccd/vinum to the equation will lower my IO throughput, but the
>question is... if I have an external hardware shelf with 3.5TB (16 250GB
>drives w/ Raid 5 from hardware) and I put a Raid 0 stripe across 3 of these
>shelves what would my expected loss of IO be?

The loss will mostly be from latency, but how much is impossible to
tell I think.

The statistics of this, even with my trusty old Erlang table would
still be too uncertain to be of any value.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.