Workload Disposition

Updated Sep 21, 2020 ·

Overview

Workload disposition is the decision about what should happen to an existing workload based on its business value, cost, complexity, and technical requirements.

There are four main directions:

Option	Description
Build	Create or rebuild a solution when it provides unique business value.
Buy	Use an existing product or managed service for commodity capabilities.
Modify	Preserve the workload but change or modernize how it runs.
Deprecate	Retire workloads that no longer provide enough business value.

The goal is not simply to move every workload to the cloud.

The goal is to choose the option that provides the most business value for its cost and complexity.

Build

Build when the workload provides a genuine competitive advantage and existing products cannot adequately meet the business requirement.

Advantages:

• Provides unique capabilities.
• Can be tailored exactly to business requirements.
• Gives greater control over architecture and features.
• Can differentiate the business from competitors.

Trade-offs:

• Higher engineering and development cost.
• Requires ongoing maintenance and ownership.
• Security, scaling, availability, and operations must be managed.
• Development may take longer than adopting an existing solution.

Building is usually justified when the capability is important to how the business differentiates itself or makes money.

Avoid building a custom solution when an existing managed service already satisfies most of the requirements at significantly lower cost.

Buy

Buy when the workload performs a commodity function that the business needs but that does not provide meaningful competitive differentiation.

Instead of building and operating the capability yourself, use an existing product or managed cloud service.

Advantages:

• Faster implementation.
• Less engineering and operational overhead.
• The provider may handle patching, scaling, and high availability.
• Often cheaper than developing and maintaining a custom solution.

Trade-offs:

• Less control over the platform.
• Vendor dependency.
• Potential feature or platform lock-in.
• Customization may be limited.

Examples include using:

• BigQuery instead of building a data warehouse
• Cloud SQL instead of operating your own database servers
• Pub/Sub instead of developing a custom messaging system

Modify

Modify when the workload still provides business value, but running it unchanged would be inefficient, expensive, or difficult to maintain.

The goal is to preserve its value while improving how it operates rather than completely rebuilding it.

Advantages:

• Preserves existing business functionality.
• Can reduce operational overhead.
• Allows the workload to take advantage of cloud services.
• Usually requires less effort than a complete rebuild.

Trade-offs:

• Some legacy architecture or technical debt may remain.
• Migration can require application changes.
• The resulting architecture may not be fully cloud-native.

Examples:

• An existing Java application could be containerized and moved to GKE.
• A self-managed MySQL database could be migrated to Cloud SQL.

Deprecate

Deprecate when the workload no longer provides enough business value to justify its cost.

Moving an unnecessary workload to the cloud does not make the migration successful.

It simply moves the operational and financial burden somewhere else.

Advantages:

• Eliminates infrastructure costs.
• Removes maintenance and operational overhead.
• Reduces unnecessary engineering work.
• Can reduce security and technical debt.

Trade-offs:

• Requires confirmation that the workload is no longer needed.
• Stakeholders may resist shutting down familiar systems.
• Dependencies and integrations must be identified before removal.

Common examples:

• Old reporting systems that have already been replaced.
• Custom integrations that have been superseded by newer services.

Migration Strategies

When the decision is to keep or modify a workload, the next question is how much change should be made during the migration.

Option	Meaning	Typical Use
Retain	Keep the workload as is for now	The system is stable or migration risk is too high
Retire	Remove the workload completely	The application is no longer needed
Rehost	Move the workload with minimal change	The business wants speed over redesign
Replatform	Make limited changes during migration	The workload can benefit from cloud managed services
Refactor	Redesign the workload for the cloud	The business wants long-term modernization

These options are often called the 5 Rs, and they help determine how much change should be introduced during migration. The right disposition depends on what the workload is doing and what the business actually needs.

• Retain when the workload still has value and the migration cost or risk is currently too high.
• Retire when the workload no longer supports a business need.
• Rehost when migration speed matters more than modernization.
• Replatform when you want cloud benefits without a full rewrite.
• Refactor when major architectural improvements are required.

Decision Framework

A simple way to make the decision is to evaluate two questions:

1. How much business value does the workload provide?
2. How much complexity or cost does it require to maintain?

The combination of these factors can guide the disposition:

Workload	Recommended Direction	Reasoning
High value + manageable complexity	Modify or Buy	Preserve the business value while reducing operational burden.
High value + extreme complexity	Phased Build	Rebuild important differentiating capabilities properly over time.
Low value + low complexity	Buy or Modify	Replace with a managed service or make small improvements where economical.
Low value + high maintenance cost	Deprecate	The workload does not provide enough value to justify its ongoing cost.

The key principle is that workloads should deliver business value proportional to their cost and complexity. A cloud migration is also an opportunity to question whether a workload should be migrated at all, rather than automatically moving everything to the new environment.