Best choice for 5k request spikes
I am building a backend that is supposed to handle 5k request spikes. The application is a photo sharing app that uses SQL for database, php to handle requests and x-sendfile to send the images to user. What is the best setup server wise?
Now i have build a HAProxy load balancer to two apache servers who have a shared folder to access images and a database server. 4 servers in total. We may install memcached to save some processing. Will this hold? Is this a good setup? Do you have any suggestions on improvements or better solutions?