Knowledge Base

Nginx configuration check fails: the size 5242880 of shared memory zone “SSL” conflicts with already declared size 1048576

Symptoms

Nginx configuration check fails with the error below:

[emerg] the size 5242880 of shared memory zone "SSL" conflicts with already declared size 1048576 in /etc/nginx/plesk.conf.d/vhosts/example.com.conf

Cause

The custom ssl_session_cache configured in /etc/nginx/nginx.conf or /etc/nginx/conf.d/ssl.conf file prevents generation of the configuration file.

Resolution

Connect to the server via SSH
Edit file /etc/nginx/nginx.conf or /etc/nginx/conf.d/ssl.conf.

Comment the line below by changing it from:

ssl_session_cache shared:SSL:1m;

#ssl_session_cache shared:SSL:1m;

Restart the Nginx service:

# service nginx restart

In some cases custom configuration added for particular domain. Check it with strace:

# strace -ffs4096 nginx -t 2>&1 | less <…> open(“/var/www/vhosts/system/example.com/conf/vhost_nginx.conf“, O_RDONLY) = 7 fstat(7, {st_mode=S_IFREG|0600, st_size=77, …}) = 0 pread64(7, “ssl_session_cache shared:SSL:10m;nssl_session_timeout 1h;nssl_buffer_size 4k;”, 77, 0) = 77