Increased memory usage by PHP-CGI processes on server after Plesk update

Dmitry Bystrov

10 months ago

Symptoms

The memory usage increased after installing Plesk updates.
RAM is used by dozens of php-cgi processes started by Apache:

# top
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
26267 johndoe+ 20 0 810324 72704 3372 S 0.0 0.5 0:01.62 /opt/plesk/php/5.3/bin/php-cgi -c /var/www/vhosts/system/example.com/etc/php.ini
10022 janedoe+ 20 0 809084 71940 2108 S 0.7 0.5 0:01.72 /opt/plesk/php/5.3/bin/php-cgi -c /var/www/vhosts/system/example1.com/etc/php.ini
996 jadedoe+ 20 0 814800 68728 10556 S 0.0 0.5 0:04.24 /opt/plesk/php/5.3/bin/php-cgi -c /var/www/vhosts/system/example2.com/etc/php.ini
Very big timeouts are specified in /etc/httpd/conf.d/fcgid.conf :

FcgidIdleTimeout 2100
FcgidProcessLifeTime 2100
FcgidMaxProcesses 300
FcgidConnectTimeout 2100
FcgidIOTimeout 2100
FcgidBusyTimeout 2100

Cause

PHP-CGI processes are consuming too much memory due to big timeout values in FastCGI configuration.

Resolution

Solution 1

Connect to the server via SSH
Open /etc/httpd/conf.d/fcgid.conf in any text editor
Decrease timeouts to lower values to finish php-cgi processes earlier, and execute service httpd reload command to reload Apache configuration. Default values are:

FcgidIdleTimeout 40
FcgidProcessLifeTime 30
FcgidMaxProcesses 20
FcgidConnectTimeout 30
FcgidIOTimeout 45
FcgidIdleScanInterval 10

Note: The drawback of this solution is the possible failure of long-running PHP scripts. If you are sure that there is no any on the server, you can follow this option.

Solution 2

Log in to Plesk, go to Domains > example.com > PHP settings and set PHP version to 7.0.33 and handler to FPM application served by nginx:

Perform these configuration changes for every domain one by one.

Note: The drawback of this solution is possible websites' downtime due to switching to nginx. For example, domain-level .htaccess files can not be handled anymore, that can lead to website downtime. That's why it was recommended to switch the websites one by one, checking their availability.

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