==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.3.1
- Deployed with iRedMail Easy or the downloadable installer? installer
- Linux/BSD distribution name and version: Debian 10
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MariaDB
- Web server (Apache or Nginx):nginx
- Manage mail accounts with iRedAdmin-Pro? yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hello Zhang,

I found that despite gzip compression is on, many well compressable items are not compressed by nginx.

Cause: MIME type is application/javascript and not (only) text/javascript.

To fix it, change

gzip_types text/plain text/css text/xml text/javascript text/json application/json application/x-javascript application/xml application/xml+rss;

to

gzip_types text/plain text/css text/xml text/javascript text/json application/json application/x-javascript application/xml application/xml+rss application/javascript;

in /etc/nginx/conf-enabled/gzip.conf

In addition to above, 6% less data with reasonable CPU consumption can be achieved by setting compression level to 6

gzip_comp_level 6;

Please check for faster page loading times and fewer traffic

Best regards,
Bernhard