From owner-freebsd-isp  Thu May  6  6:57: 5 1999
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Date: Thu, 06 May 1999 14:57:01 +0100
From: Stuart Henderson <stuart@eclipse.net.uk>
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To: Andrew McNaughton <andrew@squiz.co.nz>
Cc: Andy Angrick <angrick@netdirect.net>,
	Graeme Tait <graeme@echidna.com>, freebsd-isp@FreeBSD.ORG
Subject: Re: Apache Stress testing
References: <199905061247.AAA04038@aniwa.sky>
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> One query I have:  if my file system keeps tabs on when 
> files were last accessed, does that mean that every file 
> opened requires a disk access, even if it is cached, or 
> does this mark the cached info as dirty so that it will 
> be written at a future time?  Does anyone have any 
> experience with the effect on apache performance of 
> mounting the file system with the noatime flag?

I haven't looked at that but this makes me think of something you
might not know, I think I read it on Wired's Webmonkey section 
(general article about Apache 1.3 performance, there is a lot more
than just this - I can't remember it all atm but it might be
interesting/useful). Sorry I don't have the url handy :(

From what I remember if you have "followsymlinks no" Apache has to 
look up all the parent directories of the document directory (/ 
/usr /usr/local /usr/local/www /usr/local/www/data and any others) 
to check they're not symlinks. Similarly if "allowoverride" is not
set to anything other than "none" there is a similar lookup for
.htaccess files.

-hackers or maybe -questions would be a good place to ask about
FS cache / noatime if nobody here knows. I reckon that unless you 
actually want the access time info someplace other than apache's 
log, you might as well save the extra fs writes ;)

Stuart


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