Running stresstest to see how healthy a webserver is !?

[unleash_it]

hello dear PHP-Experts hello and good day,



the issue and topic of today: running stresstest to check how healthy the server is - and to find out why a script sometimes stopps working:


in the past few weeks i have had some issues on a server - with Wordpress and Limesurvey. I also have openend a thread here. Now the site is up again and runs well. The limesurvey-page often has thrown a page like ERR_EMPTY_RESPONSE Error (both on FireFox and on Chrome)


Since 24 h. the behaviour is better - the site is up again. see path: http://www.f-s-j.de/limesurvey/index.php/admin/index
limesurvey :: https://www.limesurvey.org/about-limesurvey/ version 3.20.02

it is installed in (between) a wordpress :: in other words: the limesurvey was installed under a folder inside my wordpress installation.
Some limesurvey-experts say that i will get all kind of issues over the time. And that it has to do with the installation-structure:

- MyDomain.TLD/limesurvey/ (LimeSurvey)
- MyDomain.TLD/ (Wordpress)

hypothesis: LimeSurvey and Wordpress tell the server to rewrite URLs for the browser. In my setup Wordpress just tries to overrule certain settings of LimeSurvey. The Limesurvey-folks recommend that i would need to check every change and update manually the htaccess file (since i am running apache).


final recommendation: To minimize work and trouble, i should install wordpress and limesurvey side by side.
we then need to redirect from MyDomain.TLD/ -> MyDomain.TLD/wordpress/, but then (after this step) i have clean folders and don't cause delays and loops when it comes to URL accessing. This safe way of installation side by side includes a special procedure: to use /w/ for wordpress and /s/ for limesurvey will keep the URL short.


Again: the error way: ERR_EMPTY_RESPONSE - after it worked very well for weeks

what can i do now!?

btw. the wordpress on the server still runs well


question: can i perfom a so called stress- or perfomance-Test to see how healthy the server is!?
in other words: is there a Performance-, Last- und Stress-Test for a Webserver out there.

note: some data:
PHP Version 5.6.39
eg. wordpress-basic-installation
https://www.limesurvey.org/about-limesurvey/download
sometimes i get the error: ERR_EMPTY_RESPONSE Error



look forward to hear from you

regards

[unleash_it]

hello again,

well i also have discussed the issue with the limesurvey-user here:

https://www.limesurvey.org/forum/instal ... eks/191580

after having mused bout the errors and the possible reasons - after having mused bout porting over the installation on subomains or a
side to side installation i suddenly saw that the site is coming back...

note: i guess that the errors ERR_EMPTY_RESPONSE - is rooted in a very very weak server - just that easy - is this possible - is this thinkable!?


Holch - one user of the limesurvey - he has got the very same installation - structure as i have.


the user holch: : in this thread you answer very interestingly :

I run Limesurvey and Wordpress in a very similar setting (Wordpress in root and LS in subfolder)
and I don't have the same problems. So while I wouldn't want to exclude this as the source of issues completely,
I would probably focus on other aspects first, as it works fine with me for quite some time now.
Of course, as Jelo says, any update in one of the two applications could start causing problems.

https://www.limesurvey.org/forum/instal ... -for-weeks

at the moment it goes very well - in other words i have no issues at the moment: Holch - is it thinkable that this error is rooted in a very slow server!? I have to admit that this seerver is very very old and will be replaced very soon (in a few weeks)

you have mentioned that you have installed limesurvey in (exactly) the same way as i did.
you also have mentioned that you did not have encountered any of the issues as i have encountered.

is this true!?

furthermore; i have googled this error - guess that it is this one:

Error 324 (ERR_EMPTY_RESPONSE): The server closed the connection without sending any data
https://stackoverflow.com/questions/886 ... ted-by-aws

website. I don't think it is Chrome browser bug either because when I open safari I don't get the error, I get a white page.Not sure what is happening or why. Basically, I am looking for the root causes for this server error.
Any ideas would be much appreciated. If you need me to provide any specific info, let me know.
Come to think of it, this error started happening because the server is pretty slow!

cf: https://stackoverflow.com/questions/886 ... ted-by-aws

- Except a CURL shows me the HTML just fine, but it's not loading up in a browser. What in the world could be causing something like this Everything was fine until last night
- @Till's curl advice is brilliant
- what about to work with Session-stickyness:
Edit: How do you manage this problem in the future when you need session stickiness? I have no idea. But there should be answers on this out there!
- ...In addition to this, GZIP needs to be disabled at the web server (apache, or other).

what do you say - is this thinkable that the server ist pretty slow!?
what bout the test-method of using curl - in the moment when encountering the issue- !?


the idea of Err Empty_Response_ being rooted in the slow server - well this would be great - since i change the server in the next few weeks. Is this idea of the possible roots thinkable - and convincing!?


note: as it runs very well at the moment i will take a closer look at the behaviour - and will try to find out if /(when) the error will be appear again.



look forward to hear from you
regards