Infrastructure as a Service (IaaS) and private cloud are related but distinct concepts. IaaS is a cloud computing service model that provides virtualized computing resources over the internet, while a private cloud is a deployment model that can use IaaS services but is dedicated to a single organization.

The key difference between traditional DR and DRaaS is the managed service aspect of DRaaS. The same fundamental phases of DR exist in both cases: replication, failover, and failback.

DRaaS offers several key benefits including reduced infrastructure costs, faster recovery times, expert management and monitoring, scalability, compliance support, and the ability to focus on core business activities while leaving disaster recovery to specialists.

DRaaS is ideal for businesses that need reliable disaster recovery but lack the resources, expertise, or infrastructure to manage it in-house. It's particularly beneficial for small to medium businesses, companies with limited IT staff, or organizations with strict compliance requirements.

Key considerations include Recovery Time Objectives (RTO) and Recovery Point Objectives (RPO), service level agreements, security measures, compliance certifications, scalability options, cost structure, provider expertise, and integration capabilities with your existing infrastructure.