We have changed the php settings to match what Divi documentation asks for, and in some cases more. We have set memory_limit to 256M, this will take caer of the majority of issues.
Max_upload_filesize and post_max_size both define how large of files you can upload as well as posts you can post. They can only equal the lowest value out of the both of them, so that is why we set them both to 256M. For instance, if max_upload_filesize = 256M but post_max_size = 128M, both values would only show 128M. Do yourself a favor and set both high.
max_execution_time is the number of seconds allowed to pass by the php program before failure. If you have a larger post, 30 seconds is not enough time. Divi asks for 180 but set this to 300.
max_input_vars represents the number of variables your server can use in a single function. Divi being a larger theme, needs a higher value, or else it will not function properly.