Single tenant vs multi-tenant SaaS: What’s the difference?

SaaS (software as a service) delivered an explosion in muti-tenant deployments. Is multi-tenancy the right choice for every organization? This article will help companies weigh single tenant vs multi-tenant with definitions and explanations of the benefits, challenges, and differences.

What is multi-tenancy?

An assessment of single tenant vs. multi-tenant starts with a definition of multi-tenancy. A multi-tenant architecture, referred to as multi-tenancy, has all users share access to a common set of infrastructure hardware and software resources. With multi-tenancy, a single infrastructure is used in place of multiple environments.

Multi-tenancy environments have each tenant physically integrated, but logically separated. For example, multiple organizations can share a single instance of configurations, data, user management, and other properties while keeping their data and processes private. In another scenario, a single instance of an application runs on one server and is used by multiple tenants whose data and work remain private.

Three common multi-tenancy models are outlined below. Varying levels of complexity and cost will drive discussions and selection. The models are explained in the context of the relationships between applications and databases.

1. Single application with a single database
2. Single application with multiple databases
3. Multiple applications with multiple databases
4. Easier scaling
5. Low cost for tenants
6. Potential performance impact based on other tenant’s activities
7. Simplest multi-tenancy environment
8. Difficult to scale
9. Higher cost
10. Reduces performance impact of neighbors
11. Supports different tenants with different requirements
12. Complex
13. Expensive
14. Highly secure
15. Tenants partitioned according to their criteria

Cases in which multi-tenancy is the right choice for a software application may include:

1. Need to support multiple users in a cost-effective cloud environment
2. Want to avoid a large infrastructural footprint
3. Lack of resources for a large deployment and the associated maintenance and support
4. Require seamless scalability options
5. Have a team of experienced developers and architects

For users who are purchasing a software application, multi-tenancy may be the right choice if the organization:

1. Allows resource or data sharing
2. Is trying to balance performance vs. cost graph in favor of cost savings
3. Requires relatively minor configurational customizations

What is single tenancy?

The assessment of single tenant vs multi-tenant continues with a review of the definition of single tenancy. A single tenant architecture runs only one instance of an application and supporting infrastructure for one organization.

As with multi-tenancy, varying levels of complexity and cost will drive the selection of a single tenant architecture. Characteristics of a single-tenant architecture include a high level of user control, especially with regard to:

1. Backup capabilities
2. Flexibility to address specific environment requirements
3. Making updates
4. Reliability
5. Security

Single tenancy may be the right choice when building a software application if the organization:

1. Is comfortable with a large infrastructural footprint
2. Does not have to support a lot of customers
3. Has no budgetary restrictions
4. Needs to provide unparalleled performance and throughput
5. Possesses the resources for a large deployment and the associated maintenance and support

Single tenancy may be the right choice when purchasing a software application if the organization:

1. Can pay a premium for their selection
2. Does not allow resource or data sharing
3. Requires extensive configurational customizations
4. Does not need to automate upgrades

Single tenant vs multi-tenant

Benefits of multi-tenancy

Reduced costs

1. Flexible payment models: Pay-as-you-go, monthly or annual subscriptions based on the number of users, usage level, or data volume
2. Operations costs shared by all tenants (e.g., hardware, software, maintenance, and support)

Flexible scalability

1. Increase or decrease resources to extend capacity or eliminate unused resources
2. Seamlessly add new users

Does not require maintenance

1. All maintenance is included, such as installing software updates and patches, maintaining availability, and managing backups
2. No need to have expert resources in-house

Better overall security

1. Security and privacy of the data processed on the multi-tenant cloud are supported and maintained by the service provider
2. Consolidated resources can more effectively manage threat and intruder detection and prevention
3. Physical and logical access controls are more stringent and tightly managed

What’s SaaS got to do with it?

Software as a service (SaaS) is one of the largest examples of multi-tenancy. A SaaS solution can run one instance of its application on one instance of a database, providing multiple tenants access via web access, with each tenant having a unique, private subdomain to access their part of the service.

Challenges with single tenancy

Reasons the single tenant vs. multi-tenant decision leads to multi-tenancy include single tenancy drawbacks such as:

1. Cumbersome management and maintenance
2. High costs
3. Inefficient resource usage
4. Requirement for dedicated administrative support
5. Time-consuming and complex deployments

Single tenant vs multi-tenant: Take time to make an informed decision

Ultimately, the single tenant v. multi-tenant decision rests on use cases, resources, and budget. Organizations are encouraged to take time to carefully evaluate single tenant vs multi-tenant solutions before making their decisions, as rearchitecting solutions and deployments can be expensive and time-consuming, in some cases even impacting the company’s ability to grow and scale.

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