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Date: Sat, 15 Oct 2005 08:56:01 -0500
From: Dan Nelson <dnelson@allantgroup.com>
To: Deepak Naidu <deepak_nai@yahoo.com>
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Cc: freebsd-questions@freebsd.org
Subject: Re: Should I increase  vfs.read_max
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In the last episode (Oct 15), Deepak Naidu said:
> Hi,
>      I am running FreeBSD 5.4 on SunFire v20 on single
> hard disk 73 GB...
> 
> I googled down some links regarding increasing IO
> performance.  It said increase vfs.read_max from 8 to
> 16. I have done that, but cant justify any
> improvement, as I am running mailserver(spam checker).
>  Should I revert to 8 or use 16.

Raising vfs.read_max is most helpful when you are reading large
sequential files from RAID arrays.  On a single-disk system, all it
does is allow sequential readers to starve random readers.

-- 
	Dan Nelson
	dnelson@allantgroup.com