[TYPO3] Stability & performance problem

[Michael Scharkow]

Piotr Burda wrote:

> hi
> i`m just reading your great article :), and i found this:
> 
> Finally, we watched out for performance killer extensions from TER. 
> Extensions that are triggered with every request are notorious, like 
> those that transform HTML code shortly before it is outputted.
> 
> we are using: Ehchanced HTML cleaner, maybe this one is slowing our system?

I have never used it, it depends on whether the HTML cleaner kills 
caching or is just introduced *before* the page is cached. I think your 
pages are cached anyway, so should not be a problem. You need to find 
out yourself if pages are cached (admin panel tells you).

> some minutes ago i`ve found a strange request:
> 
> 66.249.72.244 www.narty.pl GET /index.php?no_cache=1
> 
> arin whois said that it`s google,
> 
> and i tried to kill the server myself
> 
> using link to my main page with no_cache=1 parameter with success :(,
> after opening this link in browser and pressing F5 (+- 15 times) the 
> server was overload and instable.
> 
> Is it a bug in typo3, or a mistake in my configuration?

It's not a bug strictly in TYPO3, as many things rely on no_cache=1. But 
it is a way to DOS yourself quickly ;) Stucki came up with this issue 
last week and I proposed adding a config flag to turn this off 
completely, but it is not done yet.

However, your server should not panic even in worst case scenarios like 
"everybody calls your pages with no_cache=1".

*HINT*
Your server should easily manage 35 req/s even with no_cache=1 on.

Read on in our article, and apply the tips and tricks:

1. You *need* to run eaccelerator (or Zend optimizer) with enough memory
2. You need to make sure your MySQL does not cause much load, so 
configure the query cache, make sure you have a nice connection limit
3. You need to configure the apache, Look into max_clients in 
httpd.conf, since you get DOSed so quickly, chances are they are set too 
high: start with 64 to 100 maxclients.

And please provide some benchmarks, so I don't have to guess all the time.

Greetings,
Michael