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Date: Mon, 11 Jun 2012 08:28:49 -0600 (MDT)
From: Warren Block <wblock@wonkity.com>
To: Robert Huff <roberthuff@rcn.com>
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	(wonkity.com [127.0.0.1]); Mon, 11 Jun 2012 08:28:50 -0600 (MDT)
Cc: questions@freebsd.org
Subject: Re: speed of "dump"
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On Mon, 11 Jun 2012, Robert Huff wrote:

>
> 	Another thread, which I seem to have lost, was talking about
> dump and sizing its cache.
> 	Per my promise, appended is the log of this morning's level 0 dump,
> using C=32.  THe system is -CURRENT from March, using AMD Phemon II
> x4/3ghz and SATA 3gbit drives (one internal, one external.).
>
>  DUMP: finished in 1746 seconds, throughput 19568 KBytes/sec

Are you using -b64 ?  That can make a serious throughput improvement 
over smaller values.