Category Archives: Servers

Web : ImagickException: attempt to perform an operation not allowed by the security policy `PDF’

After updating ImageMagick to version 6.9.10.23+ from an earlier version, the following behavior occur : Thumbnails generation from PDF, XPS, PS, and EPS does not work anymore The following output can be found in the Web server error log :

This is due to the addition of a policy in the newer version that… Read More »

Linux : How to show Apache memory usage and average process size

Here is an easy way to output in a single command the Apache memory usage and average process size :

This is particularly useful when you need to calculate proper process, max clients, etc. settings.

Linux : sar command return “Cannot open /var/log/sysstat/sa27: No such file or directory”

Attempting to use the SAR (sadc) command to lookup the historical system resources consumption metrics and got the following message? Cannot open /var/log/sysstat/sa27: No such file or directory Please check if data collecting is enabled Most likely data collecting is disabled (it is the default on several systems). You need to enable data collecting and… Read More »

Linux : phpMyAdmin – Error Incorrect format parameter

Having the following error while importing a MySQL dump? phpMyAdmin – Error Incorrect format parameter Have a look at the “upload_max_filesize” value in your “php.ini” parameters. Most of the time, the dump file you are trying to import exceed that limit. Increase the value as needed.

Linux : How to change the OpenVPN lockout time policy

By default, OpenVPN has 15 minutes timeout lockout policy for consecutive unsuccessful authentication attempt (whatever you are using Local, PAM or LDAP authentication). If you want to change it to shorter or longer time period, follow these easy steps below : 1. Push the new timeout value to the configuration using this command (this example… Read More »

Linux : cPanel failed to make connection to backend: httpd-UDS

Experiencing the following error loading a Web site hosted on your cPanel server? 503 Service Unavailable And observing the following errors in the Apache logs :

In my case, this occurred after the Web site account was just migrated to a new server. This is related to PHP-FPM, that isn’t responding to serve the… Read More »