MultiTenancy

Multitenancy is a software architecture where a single instance of a software application serves multiple customers, referred to as tenants. Each tenant's data is isolated and remains invisible to other tenants.

• Tenant: An individual user, a group, or an organization that uses the shared software service but experiences it as though it is solely dedicated to their use.
• Instance: A single deployment of the software solution that supports multiple tenants.
• Isolation: Techniques that keep tenant data and configurations separate from one another to ensure privacy and personalization.

• Physical Multitenancy: Different physical machines host different tenants.
• Virtual Multitenancy: Virtualization technology allows multiple tenants to share hardware resources.
• Application-Level Multitenancy: A single application serves multiple tenants, typically providing each with a customizable experience.

• Cost Efficiency: Reduced operational costs as resources are shared among tenants.
• Scalability: Easier scaling since the architecture is designed to accommodate multiple tenants.
• Simplified Management: Centralized management and updates for software applications.

• Security Concerns: Potential risks of data breaches or leaks between tenants.
• Customization: Balancing between offering shared resources and the customization needs of different tenants.
• Performance: Ensuring that the performance is optimal and equitable across all tenants.

• Widely used in SaaS (Software as a Service) products like CRM systems.
• Employed in cloud computing platforms to optimize resource utilization.

• Multitenancy aligns with the broader trends in cloud computing and SaaS, providing a practical means of delivering services at scale.
• Physical, virtual, and application-level multitenancy represents a spectrum of implementation strategies, each with trade-offs in terms of cost, performance, and security.

• How do differing implementations of multitenancy impact the scalability and flexibility of a SaaS product?
• What best practices exist for ensuring data isolation and security in a multitenant architecture?
• How does multitenancy compare with single-instance architectures in terms of cost and operational efficiency?

• Logical Isolation: Each tenant's data is stored in separate tables within a shared database, using unique identifiers to distinguish tenant data.
• Dedicated Schema: Each tenant is assigned a unique database schema that comprises the necessary tables and views, ensuring separation at the database level.
• Separate Databases: Each tenant has their own database instance, providing the highest level of data isolation but also higher resource usage.
• Encryption: Data is encrypted at rest and in transit to prevent unauthorized access, with encryption keys managed per tenant.

• Logical isolation balances resource efficiency with data separation, suitable for environments where cost is a concern.
• Dedicated schema and separate databases increase isolation but might introduce higher complexity and costs.
• Encryption serves as a critical layer of security across all types.