What is Entry Processes Limit (EP) in a CloudLinux server?

The Entry Processes Limit, also know as “Apache concurrent connections” limit is one of the main LVE parameter in CloudLinux. We already discussed the basics of CloudLinux and its administrations. CloudLinux is a Linux based Operating system especially used in a shared environment which isolates each user in its own light weight virtualized environemnts (LVE) which consumes predefined amount of resources allocated for each user. That is, each user will be in a caged environment. The resource usage of any user won’t affect the stability of another users.

Entry Processes Limit control the number of entries into LVE. It counts the processes enters into LVE and increment the counter, likewise, it decrement the counter when the process leave the LVE.

Note 1 : The process enter’s into LVE when there is a new HTTP request for CGI/PHP.
Note 2 : It does not count processes that are created inside LVE itself.

Importance of Entry Processes Limit

This technology was created to prevent DDoS attacks to web servers. One of the most famous attack to a web server is creating multiple HTTP connections. Those HTTP connections to a web server can slow down the server. Once all Apache slots are used up, no one else (new connections to server) will be able to connect to the web server, causing it to appear to be down. In this case the CPU usage will be high and the page serving speed of Apache will be slow.

The Entry Processes Limit (Apache concurrent connections’ limit) is created to mitigate this DDoS to server. This will limit the total number of connections to Apache. Once the number of concurrent connections reached its limit, the web server serve the error page “508 Resource Limit Reached.” For more details, see this article on 508 Resource Limit Reached.

How to check the Entry Processes usage for a user?

This can be done from the cPanel or from the server CLI (command line interface). Here I’ll give you a detailed explanation on how to check the EP usage for an account.

How to check this via cPanel?

1. Log into cPanel.
2. Then go to, Logs >> Resource Usage; to get a detailed view.

Entry Processes Limit

Or you can see those details from the left panel.

Entry Processes Limit2

How to check resource usage details from commandline?

From shell, you can see those details simply by using the “lveinfo” command. Please see the details pasted below:

Syntax

# lveinfo -u $username

Sample output

# lveinfo -u crybit
+-----------+-----------+----+----+----+---+---+----+---+---+---+-----+-----+-----+---+-----+-----+-----+-----+
|    From   |     To    |aCPU|mCPU|lCPU|aIO|mIO|lIO |aEP|mEP|lEP|aPMem|mPMem|lPMem|EPf|PMemF|aIOPS|mIOPS|lIOPS|
+-----------+-----------+----+----+----+---+---+----+---+---+---+-----+-----+-----+---+-----+-----+-----+-----+
|05-30 11:35|05-30 11:40| 0  | 0  | 4  | 0 | 4 |4096| 1 | 1 | 40|62.6M|64.2M| 2.0G| 0 |  0  |  0  |  0  | 1024|
|05-30 11:40|05-30 11:45| 0  | 0  | 4  | 1 | 36|4096| 1 | 2 | 40|63.6M|66.1M| 2.0G| 0 |  0  |  0  |  4  | 1024|
|05-30 11:44|05-30 11:45| 0  | 0  | 4  | 1 | 4 |4096| 1 | 1 | 40|63.6M|63.6M| 2.0G| 0 |  0  |  0  |  0  | 1024|
|05-30 11:45|05-30 11:46| 0  | 0  | 4  | 0 | 2 |4096| 1 | 2 | 40|58.4M|64.9M| 2.0G| 0 |  0  |  0  |  0  | 1024|
|05-30 11:46|05-30 11:47| 0  | 0  | 4  | 0 | 2 |4096| 1 | 1 | 40|63.6M|63.6M| 2.0G| 0 |  0  |  0  |  0  | 1024|
|05-30 11:47|05-30 11:48| 0  | 0  | 4  | 1 | 4 |4096| 1 | 2 | 40|63.6M|64.8M| 2.0G| 0 |  0  |  0  |  0  | 1024|
+-----------+-----------+----+----+----+---+---+----+---+---+---+-----+-----+-----+---+-----+-----+-----+-----+

See the columns aEP, mEP and lEP for more details.

Arunlal Ashok

Sr. Linux Server Administrator. I'm managing Linux servers since 2012. I started this blog to share and discuss my ideas. Check My Profile in uPwork (oDesk) and create a job, if you need any administration help. Thanks!!

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