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Date: Mon, 19 Sep 2011 08:48:08 -0500 (CDT)
From: Bob Friesenhahn <bfriesen@simple.dallas.tx.us>
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To: Peter Jeremy <peterjeremy@acm.org>
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Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org>
Subject: Re: ZFS obn FreeBSD hardware model for 48 or 96 sata3 paths...
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On Mon, 19 Sep 2011, Peter Jeremy wrote:
>
> ZIL will only be useful if you do lots of sync writes.  L2ARC won't
> help write performance.  Heavy write load implies you want mirroring

L2ARC can substantially help write performance in the case where a 
partial block is updated.  It avoids the 'read' part of the 
read/modify/write cycle.  Of course it only helps if the L2ARC is much 
more responsive than the main store.

Bob
-- 
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/