Each time someone browses a page on your website, the webserver works to serve up the page to the client. While the webserver is working on that page request, it is using one entry process to do so. When it has finished returning the page to the client, it is no longer using an entry process for that request.
For example, say you have a web pages on your website which takes 0.1s to load. 10 different people could load that web page every second. Provided the next visitor to your site only asked for that webpage after the previous visitor had finished, you would only ever need 1 entry process to serve up that page to all 10 visitors. However if all 10 visitors ask for the webpage at precisely the same instant, all 10 visitors would be served the page 0.1 seconds after that, but you would have had 10 entry processes running during that 0.1s period.
Cron jobs, shell scripts and other commands also use one entry process for the duration of the time they are running.
Simultaneous users browsing your website uses server resources. Entry processes are therefore one of the resources we have to limit, in order to protect other users of a server from any one user's excess.
If you are using all of your allotted entry processes, and another visitor tries to browse your website before the entry process count drops back below the limit, that next visitor would experience a 508 error. Because breaching entry process limits results in errors, not just slowed down service, we've been very careful to make sure these limits are set amply high enough for normal use.Tags: entry processes