iam useing Apache/2.0.61 (Unix) now i planned to increase the max_clinets to 300 for that desided to increase the HARD_SERVER_LIMIT i open the path /usr/local/apache/include/httpd.h when i tried to edit the HARD_SERVER_LIMIT i can able to find that line in httpd.h any idea help me in this issue
The correct httpd.h should be located at /home/cpeasyapache/src/include/httpd.h but you don't necessarily need to change it directly, as cPanel already has an option to raise SERVER_LIMIT.
You may simply login at cPanel, go to Software > Apache Update:
1. Profile: Previously Saved Config [Start customizing based on profile]
2. Apache Version: (your choice) [Next Step]
3. PHP Major Version: (your choices) [Next Step]
4. PHP Minor version: (your choices) [Next Step]
5. Short Options List: (your choices) [Exhaustive Options List]
6. Exhaustive Options list: [CHECK] Raise Hard Server Limit
7. Save and build
The above process can be done via SSH as well (using /scripts/easyapache) and finding similarly "Raise Hard Server Limit" in order to enable it and then recompile Apache.
Wen you choose "Raise Hard Server Limit" (via cPanel or SSH), cPanel patches /home/cpeasyapache/src/include/httpd.h (using /home/cpeasyapache/src/cppatch/raise_hard_server_limit.patch) in order to increase HARD_SERVER_LIMIT from 256 to 2048.