New features in Apache HTTP Server 2.4.x
Apache 2.4.1 was released in Feb 2012 with much great enhancement and new features. The latest version as I write is 2.4.10 released in July 2014.
In this article, I will talk about some of the significant enhancement, new features included in Apache 2.4 version.
KeepAliveTimeout: It’s possible to specify KeepAliveTimeout in milliseconds with this version. To do so, just add KeepAliveTimeout directive in httpd.conf file.
KeepAliveTimeout 5 #Obviously you have to change this value from 5 to something you wish.
Memory Usage: Apache 2.4 claims to use less memory than 2.2.x
Event MPM: Event MPM (Multi-Processing Module) is now fully supported. In an earlier version, it was experimental.
mod_ssl: support OCSP stapling, can share SSL session data between servers through Memcached.
mod_proxy: Location and LocationMatch block in ProxyPass directive offer the significant performance advantage.
mod_heartmonitor, mod_lbmethod_heartbeat: This allows mod_proxy_balancer to check the number of active connections on the backend server and perform load balancing.
mod_auth_form: This will enable you to use HTML login form to restrict access. This module has a dependency on mod_session, and these make use of HTTP cookies.
mod_allowmethods: Now you can restrict HTTP methods in your Apache instance with the simple configuration.
<Location /> AllowMethods GET HEAD </Location>
mod_ratelimit: if you are running a web server on low bandwidth or just want to limit the bandwidth, this module is for you. This can restrict client bandwidth to your configured location in httpd.conf file.
<Location /downloads> SetOutputFilter RATE_LIMIT SetEnv rate-limit 400 </Location>
Note – rate-limit is in KiB/s
mod_data: This module converts response body into an RFC2397 data URL. Data URL is useful when you want to reduce the number of connections while loading page/application. This can also be included in PHP languages.
I believe above are significant changes in Apache 2.4. You may also refer the official Apache 2.4 page for complete details.