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From: "Alexander Zagrebin" <alexz@visp.ru>
To: "'Steven Hartland'" <killing@multiplay.co.uk>,
	<freebsd-current@freebsd.org>
References: <39309F560B98453EBB9AEA0F29D9D80E@vosz.local>
	<4497C65B2FB14CE781BABF07F396841D@multiplay.co.uk>
Date: Fri, 18 Dec 2009 11:21:37 +0300
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Subject: RE: 8.0-RELEASE: disk IO temporarily hangs up (ZFS or ATA
	relatedproblem)
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Big thanks for your reply! 

> We see a very similar pattern on straight ufs disks on an 
> areca controller. Machine
> console becomes totally unresponsive 30 or so seconds at a 
> time, so it maybe
> something more intergral to device operation, buffercache or 
> something?

In my case console is responsive, but there are delays when
starting command due to disk busy.

> The IO load on the machine is being generated by updating 
> rrds files in mrtg
> for a few hundred switch ports and a few thousand servers.

I'm noticing delays (lockups) even if system is idle.

-- 
Alexander Zagrebin