Why Does Apache Fail to Run Some Sites and Not Others?

PostAlmostAnything

Well-Known Member
Mar 3, 2020
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Portland, Oregon
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Website Owner
Have you ever had a situation in which some websites under the same cPanel account won't load while others will? This has me wondering what if anything cPanel does to decide which website to run and which ones not to. This is a strange situation for me in which I have a Wordpress multisite installation in which some subsites go down even though the main site and other subsites are running just fine.

In the past, this problem could be quickly solved by logging into WHM and restarting Apache but now that doesn't seem to work. There seems to be something which is periodically preventing this subsite from running even though it is part of the same Wordpress installation of other sites running just fine. I try restarting Apache and the problem persists.

This makes me wonder how Apache decides which sites to run and which ones not to in cases of high load. Is there anything I can check for in cPanel and change so that all sites load?

This situation reminds me of times my IIS server (different server) has turned off applications or stopped websites. In those cases I can simply login to RDC and restart the site or app, but cPanel does not appear to have a site by site restart feature. I am currently running the Media Cleaner plugin on one of the sites still running so I can't try to restart the server until that scan is done, but that might take a few hours. Do I have any recourse in the meantime?

It feels like something is telling the computer that because sites A, B, and D are consuming a lot of resources, so don't load site C for now. I want to make sure site C loads no matter what unless that "what" is enough to bring down all 4 sites or at least find a way to tell the system to kill site B instead of site C.
 
Last edited:

cPRex

Jurassic Moderator
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Oct 19, 2014
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Hey there! Apache doesn't decide anything - even though it may feel like it, I promise there isn't a gnome or ghost in there that just decides to not run your site for a period of time :D

We'd need some additional details as to what is happening. When the site isn't working, what errors do you get in the browser? What shows up in the Apache error log at that time (/etc/apache2/logs/error_log)?
 

PostAlmostAnything

Well-Known Member
Mar 3, 2020
97
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Portland, Oregon
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Website Owner
I don't really have any error to show for this. The experience basically is this, I run something on site A which consumes a lot of resources. Usually a Wordpress plugin like Media Cleaner or Delete Duplicate Posts on sites with tens and in some cases hundreds of thousands of posts. The operation runs slowly and surprisingly the sites which suffer first tend not to be the one running the plugin but some other site under the same cPanel user account.
 

cPRex

Jurassic Moderator
Staff member
Oct 19, 2014
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Thanks for the additional details. This sounds like the perfect use case for CloudLinux, as that operating system restricts users so one busy site doesn't take down or overload an entire system.

You can find more details about this here:

 

PostAlmostAnything

Well-Known Member
Mar 3, 2020
97
2
8
Portland, Oregon
cPanel Access Level
Website Owner
Thanks for the additional details. This sounds like the perfect use case for CloudLinux, as that operating system restricts users so one busy site doesn't take down or overload an entire system.

You can find more details about this here:

I wish something could be done in cPanel like the application pooling feature of IIS. By giving each site on an IIS server its own application pool, usually you can limit performance problems associated with high use of the site to just that app pool so that all your other sites run alright despite one being overwhelmed.