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Grade: Server: "Configure entity tags (ETags)"... Incorrect?   Message List  
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Re: [exceptional-performance] Re: Grade: Server: "Configure entity tags (ETags)"... Incorrect?

But no one is infallible. Perhaps the yslow rules should say "Disable ETags." If I'm happy using Expires (and I am), 
then I don't want to add unused functionality or extra bytes on each request, with ETag headers. I think that the other
way (using ETags instead of Expires) is equally valid. 

An eternal annoyance for me is the default Apache httpd.conf with thousands of lines of comments, and commented out settings. I much prefer to see configuration files that are concise and minimal.


On Jul 9, 2009, at 7:10 AM, dereck009 wrote:



>
> Correctly configured they can be useful, but as they are configured
> out of the Box on Apache and IIS they are recipe for confusion (as
> appears to be in this case!)
> 
> So YSlow takes the pragmatic approach and just recommends plain disabling them.
> 
> 

The Yslow rules says: "Configure ETags" not "Disable ETags".

And if you configure your ETag mechanism, Yslow will give you the points, and it won't hurt your grade either.

To use non-server specific ETags, do it like this, in your apache config, or htaccess files:

FileETag MTime Size

- Dereck009




Thu Jul 9, 2009 1:51 pm

alohashirt99
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I tried pointing YSlow 2.0.0b4 using YSlow V2 rulesets to evaluate riktor.com, and it told me the following, which I suspect is not true... ... Grade C on...
brainsto
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Jul 8, 2009
10:00 pm

The point is that ETag's aren't necessary for static content and (generally) shouldn't be used because the configuration can easily be messed up. Unless I'm...
Patrick Meenan
pmeenan
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Jul 8, 2009
10:50 pm

Pat, Yeah, I think you have the headers confused. For each transaction (the first is the default text/html web page, the second is the "new-logo.gif" image,...
brainsto
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Jul 9, 2009
2:46 am

YSlow is telling you to turn off ETags in apache so that the Etags header is never sent....
Philip Tellis
philiptellis
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Jul 9, 2009
7:41 am

Why do you think that ETags aren't necessary for static content? Not, that I'm saying they ARE necessary for static content, but where should they be...
brainsto
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Jul 9, 2009
2:52 am

There is an academic paper that discusses this issue, but I must confess that I don't agree with the author's analysis. My opinion is that The Right Way(TM) to...
Peter Booth
alohashirt99
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Jul 9, 2009
6:08 am

For static content, Etags duplicate the functionality of Last-Modified. That in itself is wasteful of bandwidth and a tiny bit of processing overhead. Etags...
Barry Hunter
b_b_hunter
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Jul 9, 2009
8:34 am

... The Yslow rules says: "Configure ETags" not "Disable ETags". And if you configure your ETag mechanism, Yslow will give you the points, and it won't hurt...
dereck009
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Jul 9, 2009
11:11 am

... Ah sorry! I was working from memory on the article that Patrick linked to (well actually the equivalent chapter in the book), not actually the YSlow rules....
Barry Hunter
b_b_hunter
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Jul 9, 2009
11:51 am

But no one is infallible. Perhaps the yslow rules should say "Disable ETags." If I'm happy using Expires (and I am), then I don't want to add unused...
Peter Booth
alohashirt99
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Jul 9, 2009
1:52 pm

Here's the write-up from Yahoo (Steve?) on the impact of using ETags and why they are generally not required: ...
Patrick Meenan
pmeenan
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Jul 9, 2009
11:37 am
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