Date: Tue, 25 Feb 2003 15:47:34 -0800 From: Daxbert <daxbert_news@dweebsoft.com> To: Christian Weisgerber <naddy@mips.inka.de> Cc: "" <freebsd-questions@FreeBSD.ORG> Subject: Re: dump: skewed I/O, why? Message-ID: <1046216854.3e5c00960e433@ra.dweebsoft.com>
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Quoting Christian Weisgerber <naddy@mips.inka.de>: > During a dump(8) of a filesystem on da0 to a holding file on da1, > with nothing else going on, iostat(8) reports figures such as these: > > da0 da1 cd0 cd1 > KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s > 64.00 148 9.28 64.00 24 1.52 0.00 0 0.00 0.00 0 0.00 > 64.00 138 8.61 61.67 24 1.47 0.00 0 0.00 0.00 0 0.00 > > Why is the I/O ratio so skewed towards reading? > > And yes, this uses dump's recently introduced -C cache option. It might be helpful to know what argument you're passing to dump and how you are redirecting the output. I normally redirect the output to a compression utility and then to disk... so, for me what you're seeing is normal. However, I gather from your surprise that you're not using a compression utility? --daxbert To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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