Below is the list of main server setting parameters and the recommended values. If you can't change it by yourself, you must contact your host provider to do it.
post_max_size: Sets max size of post data allowed.
post_max_size = 25M
upload_max_filesize: Sets the maximum size of an uploaded file.
upload_max_filesize = 40M
max_input_time: Sets the maximum time in seconds a script is allowed to parse input data, like POST and GET
max_input_time = 300
max_execution_time: Sets the maximum time in seconds a script is allowed to run before it is terminated by the parser.
max_execution_time = 300
memory_limit: Sets the maximum amount of memory in bytes that a script is allowed to allocate
memory_limit = 256M
max_input_vars: Sets the number of input variables may be accepted
max_input_vars = 4000
If suhosin patch is installed, change the following parameters to the specified values.
php_value suhosin.post.max_array_depth 100
php_value suhosin.post.max_array_index_length 128
php_value suhosin.post.max_name_length 128
php_value suhosin.post.max_totalname_length 512
php_value suhosin.post.max_value_length 2000000
php_value suhosin.post.max_vars 5000
php_value suhosin.request.max_array_depth 100
php_value suhosin.request.max_array_index_length 128
php_value suhosin.request.max_name_length 128
php_value suhosin.request.max_totalname_length 512
php_value suhosin.request.max_value_length 2000000
php_value suhosin.request.max_vars 5000
*Your site might not really consume these values but what we recommended is just to make sure that although your site is large, the setting up process will get smooth. You may try to decrease some value if you feel it's too big or you can decrease values after you finish setting up website.