Migrating InterSystems IRIS and InterSystems IRIS for Health from on-premises to the cloud offers many advantages for Application Providers and Solution Providers. These advantages include simplified operations, access to flexible resources, and enhanced resilience. Companies no longer need to worry about the physical constraints and expenses associated with maintaining on-prem infrastructure, such as power and space requirements and expensive computer hardware.

One of the most compelling benefits is the ability to accelerate speed to market. By removing the burden of infrastructure maintenance, cloud environments enable faster development and deployment cycles, allowing businesses to respond quickly to market demands and opportunities. Operational costs are also lowered, because companies can scale resources up or down based on actual needs, leading to more efficient use of capital. Moreover, migrating to the cloud can contribute to a reduced carbon footprint by optimizing energy usage through shared cloud infrastructure.

Transitioning to the cloud may involve significant changes. Companies may benefit from a more operational focus, managing and optimizing cloud resources continuously. This shift may require changes to business models, reconsideration of margins, and strategies for scaling operations up or out. While requiring more investment, embracing these changes can lead to improved agility and competitive advantage in the marketplace.

Architectural Choices in Cloud Migration

When considering the simplest cloud migration, lifting an existing on-premises application to one of the public clouds requires companies to choose one or more services (AWS, Azure, Google, or another). Companies then face an important architectural choice: migrate entirely to the cloud or create a prem-to-cloud hybrid cluster. Both InterSystems IRIS and InterSystems IRIS for Health fully support either option. A hybrid cluster mirrors the on-prem instance to the cloud asynchronously. This alternative can be helpful in situations such as when the OLTP continues to run on-prem, but the cloud instance provides support for analytics, reporting, and other read-only operations.

Migration Options

Each architectural choice for cloud migration has advantages and limitations,  making it essential for companies to evaluate their specific needs and goals when planning a cloud strategy. The first step is to choose between a full move to the cloud or a hybrid setup.

The Lift & Shift choice allows leveraging of cloud benefits while maintaining ownership of a single copy of InterSystems IRIS.

The Hybrid choice combines the stability and familiarity of on-premises systems with the flexibility and scalability of the cloud.

See our online documentation for more information on Mirroring.

Multi-Tenant vs. Single Tenant Architecture with InterSystems IRIS

Although migration does not require changes to your tenancy method, the cloud offers powerful options for scaling and billing. For this reason, you may want to re-evaluate your tenancy model. For any of our offerings, when deploying InterSystems IRIS applications in the cloud, companies can choose between the following architectures for multiple customers:

• Single Tenant: Multiple deployments; one for each of your customers.
• Multi-Tenant: Multiple customers on a single deployment.

Each architecture offers distinct advantages and drawbacks. This is especially important for application and solution providers with solutions built with InterSystems IRIS technology that have large numbers of customers, are destined for major expansion, or that house sensitive or regulated data.

Scaling of Resources and Operations

• Multi-Tenant: Scaling a multi-tenant environment involves adding resources to a single shared instance for each customer (tenant), which can be more cost-effective and simpler to manage. However, the performance of one tenant can affect others if adequate resources are not allocated, leading to resource contention.
• Single Tenant: Scaling a single tenant environment means provisioning more resources for each customer individually. While this offers more predictable performance, the need for additional infrastructure and management overhead can make this choice more complex to scale.

Isolation of Data

• Multi-Tenant: In a multi-tenant configuration, multiple tenants share the same instance of the application and database. Data isolation is achieved through softwarelevel partitioning, ensuring that each tenant’s data remains secure and separate from others. This approach can be efficient in its use of resources but can require robust security measures to prevent data breaches.
• Single Tenant: With a single tenant architecture, each customer has a separate instance of the application and database. This setup provides a higher level of data isolation, as each tenant’s data resides in a separate environment. This choice can be more secure and easier to manage, facilitating compliance with data protection regulations. 

Migration Methods

Multiple approaches are available to migrate your InterSystems IRIS solution from on-premises to the cloud service of your choice.

The two most common methods are described next. They both start with the same step of mirroring an existing deployment to the cloud, but then diverge.

Choosing Mirror or Lift-and-Shift

Both the mirror method and the lift-and-shift method start by copying your existing InterSystems IRIS from on-prem to a cloud platform. Once the cloud copy is synchronized with the on-prem instance, you make a final choice of where the migration path ends:

• Mirror: Continue to use the on-prem instance as primary and the cloud instance for backup and read-only operations, like analytics and machine learning. The cloud instance is asynchronous but periodically updated.
• Lift-and-Shift: With the on-prem primary instance and the cloud-based secondary instances now in sync, “fail over” operations from the on-prem instance to the cloud copy, which now becomes the primary subsequently for all operations (not just readonly). At that point, the on-prem deployment can be archived as a snapshot backup.

Mirroring your existing local InterSystems IRIS instance to the cloud is the most common, resilient, and straightforward way to migrate your on-prem deployment. For more information, see the Server Migration Guide in our online documentation.

More articles on the subject:

• How to set up a mirror programmatically
• IRIS Mirror in the cloud (AWS)
• VIP in GCP
• Orchestrating Secure Management Access in InterSystems IRIS with AWS EKS and ALB

Source: Lifting InterSystems IRIS to the Cloud