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Date: Sat, 22 Jan 2011 17:27:14 +0000
From: Bruce Cran <bruce@cran.org.uk>
To: Karl Pielorz <kpielorz_lst@tdx.co.uk>
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Cc: freebsd-fs@freebsd.org
Subject: Re: Write cache, is write cache, is write cache?
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On Sat, 22 Jan 2011 15:51:21 +0000
Karl Pielorz <kpielorz_lst@tdx.co.uk> wrote:

> I'll have a look at those - I'm more interested in finding a tool
> that will write data both with, and without the "don't cache this"
> flag(s) set - to see if the performance is the same (you would hope
> that regardless of the BIOS setting that writing entirely data that's
> marked not to be cached, the performance would 'sink' back down to a
> sedate 12Mbytes/sec) - if it doesn't, something is lying somewhere :)

sysutils/fio supports that: just add "fsync=x" to the
configuration file and it'll send a request to the OS to flush the data
to disk every x blocks.

-- 
Bruce Cran