As the CISO of a publicly traded company, ensuring high availability of our systems is paramount. To achieve this, I would implement a multi-faceted approach focusing on redundancy, robust monitoring, regular maintenance, and comprehensive disaster recovery planning. A key strategy in this approach would be cloud migration and the adoption of a hybrid architecture.

Moving appropriate systems and services to enterprise-grade cloud platforms like AWS or Azure would be a priority. These cloud providers offer high availability guarantees through their SLAs, which is crucial for a public company where system uptime directly impacts revenue and stock price. A hybrid cloud architecture allows us to leverage the scalability and reliability of cloud services while maintaining control over sensitive on-premises systems. This approach provides flexibility in resource allocation, enables rapid scaling during peak demands, and enhances our disaster recovery capabilities. Additionally, cloud services often include built-in redundancy and failover mechanisms, further bolstering our system availability. By carefully balancing cloud and on-premises resources, we can optimize our infrastructure for both performance and reliability, ensuring that our critical systems remain available even in the face of unexpected challenges.