A company hosts a two-tier website that runs on Amazon EC2 instances. The website has a database that runs on Amazon RDS for MySQL. All users are required to log in to the website to see their own customized pages. The website typically experiences low traffic. Occasionally, the website experiences sudden increases in traffic and becomes unresponsive. During these increases in traffic, the database experiences a heavy write load. A solutions architect must improve the website's availability without changing the application code. What should the solutions architect do to meet these requirements?