Use easyapache to recompile apache and php. Find and enable the module "deflate"
Some things to understand when using gzip:
- Currently, no global configuration is done automatically. This means it is installed but it is not doing anything yet.
- It can be configured on a per website instance. Active it using the "Optimize Website" link in cPanel under Software/Services.
Further settings can be set in your .htaccess to adjust how your content is compressed.