That is a new one to me too. I could see it on a site that gets millions of views, but not something getting 1-2k visitors a day.

Is there anything super non-standard about it? such as:
- a graphics site pulling loads and loads of images?
- tricky 'cache' issues where the scripts uses something like wget or curl to pull the page back off the server?

I'd almost think there is a coding bug somewhere. Ask the host for some log files detailing what concurrent connections means.

btw: if you switch the server to http/2, it can pipeline connections. So a request of a page, can send all the resources over the same connection (it is what I did here to speed things way up). That and Brotli Compression (both are easy to turn on in either apache or cpanel).

Is there anything super non-standard about it? such as:
- a graphics site pulling loads and loads of images?
- tricky 'cache' issues where the scripts uses something like wget or curl to pull the page back off the server?

Nope, nothing non standard or tricky, pure text and jpgs, the pages are built on the fly. The cache I wrote it's as simple as printing the final page to a file, and then if cache is turned on, a script directly loads and prints the content of that file to the browser. All the content is also compressed either way.

I'd almost think there is a coding bug somewhere. Ask the host for some log files detailing what concurrent connections means.

I don't understand this bit. I got lost there. I'm not having any issues, just reading the specs on possible new shared web hosting options and suddenly found this thing described on a few "X concurrent connections on this plan", more on the others, etc.

>I'd almost think there is a coding bug somewhere

A configuration issue maybe. Keep Alive settings can affect 'concurrent' connection time.

Other than that, I just can't imagine a normal website bumping up against any limits on 2k uniques a day.

If there is a control panel, can you tweak apache settings?

> 20, 25, and 35 concurrent connections as the limit.

If you have control of the apache, man turn on http/2.
[docs.cpanel.net...]
It will cut your total connections by a bunch.
Also if you are running any standard libraries (jquery...etc), then point those at Google or other provider that allows open linking..

Solved. Thanks for the help Brett.

A configuration issue maybe. Keep Alive settings can affect 'concurrent' connection time.

True. I wasn't aware of this.

If there is a control panel, can you tweak apache settings?

Nope, it's configured by the admins on shared hosting at account level.

If you have control of the apache, man turn on http/2.

That's great info.

I know have a more clear understanding on what concurrent connections mean, sadly when I read at diff places they talked about diff things (CGI, others talked about PHP, and others talked specifically about http requests, so I was confused and due to reading "CGI", I wondered if my CMS would be affected as it's written on Perl.

Now I understand a connection (under this context) means a request over a script, and only 10/20 (depending the case) are allowed as per server configuration at the same time, every request outside this limit will be queued, put in wait list, and there is also a setting for how long processes can stay alive.

What confused me the most is, I never noticed any webhosting company talking about this regarding shared hosting, and felt curious when I found it right now while checking new options to migrate some sites. Turns out most keep a limit of 15/20 for a one website setup, and most keep a limit of 25 for multiple websites on the same account, and more for more complex configurations.

Turns out, 25 is ok for my CMS even for higher traffic.

Thanks again, it's solved.