On-premises to cloud migration: Strategy, steps, and best practices

For most organizations, on-premises to cloud migration is no longer a question of if but how. According to Precedence Research, global cloud spending is projected to surpass $5.9T by 2035, and the pace of enterprise cloud migration is accelerating. What has changed recently is the level of sophistication companies bring to the process: fewer all-or-nothing moves, more deliberate workload-by-workload decisions, and a clearer focus on what comes after migration.

Explore our guide and discover key decisions, strategies, and steps involved in moving from on-premises infrastructure to the cloud.

The main advantages of on-premises to cloud migration

The business case for cloud migration has grown stronger with each passing year, driven by rising infrastructure costs, competitive pressure, and new demands around AI and data. The advantages span finance, operations, and technology, and they tend to reinforce each other. Here is what organizations consistently gain:

Flexible cost structure

On-premises infrastructure runs on a capital expenditure model: you buy hardware, maintain it, and eventually replace it, whether or not you fully utilize it. The cloud shifts that to operational spending, where you pay for what you use. For workloads with variable demand, this can translate into meaningful savings. For example, a 2024 study found that organizations migrating to Microsoft Azure achieved an average three-year ROI of 704% [1], driven by lower infrastructure costs and reduced downtime.

That said, unmanaged cloud spending can spiral quickly. Without proper governance, many organizations end up paying more, not less. The benefits materialize when migration is paired with a FinOps discipline, which includes ongoing cost monitoring, tagging policies, and rightsizing.

Scalability and speed

Provisioning a new server on-premises can take weeks. In the cloud, it takes minutes. For engineering teams launching new services, running experiments, or expanding into new markets, that difference compounds over time. Competitors who operate on cloud infrastructure simply move faster.

Support for AI and modern workloads

Building Machine Learning pipelines, running inference at scale, or experimenting with large language models requires elastic compute resources. On-premises infrastructure rarely provides them without significant capital outlay. Meanwhile, cloud providers offer purpose-built GPU instances, managed AI services, and pre-integrated data platforms that would require a considerable investment to replicate in a private data center.

Enhanced security and compliance

Cloud providers hold extensive security certifications and invest heavily in physical infrastructure protection. This raises the baseline for many organizations, particularly smaller ones with limited dedicated security resources.

However, cloud security works differently from on-premises security. Providers secure the underlying infrastructure, but customers remain responsible for everything built on top of it. Moving from on-prem to the cloud means taking ownership of identity management, access controls, data classification, and compliance configuration. When organizations get these right, cloud infrastructure can offer a more agile and scalable approach to compliance than traditional on-premises systems.

Hybrid vs single cloud vs multi-cloud for on-premises to cloud migration

One of the most important shifts in enterprise cloud strategy is recognizing that full migration is not always the right answer. Gartner projects that 90% of enterprises will operate in hybrid cloud environments by 2027 [2], keeping some workloads on-premises while moving others to the cloud. This hybrid approach enables organizations to retain certain systems while benefiting from the flexibility and scalability of the cloud for others.

Workloads that may benefit from staying on-prem include:

• Latency-sensitive applications that require single-digit millisecond response times;
• Compliance-bound data subject to strict residency requirements (GDPR, HIPAA, industry regulations);
• Stable, predictable workloads where on-premises costs are already optimized, and cloud economics offer no advantage;
• Legacy systems that are tightly coupled to physical infrastructure and require extensive re-architecture to migrate.

A well-planned on-premises to cloud migration strategy begins with a thorough workload assessment rather than a blanket directive to move everything. The goal is to put each application and dataset in the environment where it performs best and costs least. That decision starts with understanding what cloud infrastructure models are available and what each one is suited for.

Selecting the right cloud infrastructure model

Before selecting a migration strategy, organizations need to decide which cloud environment they are moving toward. Here’s a quick comparison of the four main models:

Most enterprise migrations end up in hybrid or multi-cloud territory, often starting with a public cloud target for specific workloads and evolving from there.

Read more: 7 key steps to develop a hybrid cloud strategy

The 7 Rs: Choosing the best cloud migration strategy

Not every application migrates the same way. For on-prem to cloud migration, teams need a consistent framework for deciding how to handle each workload. That is where the 7 Rs come in, a model widely adopted by AWS, Azure, and Google Cloud. Below, our experts break down each approach and when to use it.

1. Rehost

Rehosting means moving applications to the cloud as-is, without modification. It is the fastest and easiest approach to execute, though it doesn’t take advantage of cloud-native features. Rehosting is a good starting point for straightforward workloads or when speed is the priority.

2. Replatform

Replatforming involves making targeted, low-risk modifications during on-premises to cloud migration. For example, switching from a self-managed database to a managed cloud database service. The application logic stays the same, but the infrastructure is updated to reduce maintenance overhead.

3. Refactor

Refactoring means redesigning an application to take full advantage of cloud-native capabilities such as containers, serverless functions, and microservices. It’s the most demanding approach to cloud workload migration in terms of time and investment, but it also offers the highest long-term payoff. Refactoring makes the most sense for high-value applications where scalability and agility are critical.

4. Repurchase

Repurchasing involves retiring a custom-built or legacy application and replacing it with a commercial SaaS solution. It is common in areas such as CRM, HR, and ERP, where mature, off-the-shelf products are available. This approach can significantly reduce the ongoing development and maintenance burden.

5. Rebuild

Rebuilding takes the most radical approach: starting from scratch using cloud-native tools and architecture. It suits cases where an existing application is too outdated to refactor but too strategic to retire. Of all seven options, this is the most resource-intensive.

6. Retire

Retiring has a straightforward goal: decommission applications that are no longer needed. During a migration assessment, organizations frequently discover that some of their workloads are redundant or unused. Removing them reduces cloud costs and simplifies the overall environment.

7. Retain

Retaining simply means keeping certain applications on-premises because migration is not technically feasible, cost-effective, or compliant. Not everything needs to move. Retaining decisions should be documented and revisited as circumstances change.

N-iX experts note: A real migration portfolio typically uses several of these strategies simultaneously. Most organizations end up combining rehosting for speed, replatforming where quick wins are available, and refactoring for their most critical and high-value applications.

Choosing the right strategy for each workload is the foundation of a successful migration. The next step is putting that plan into motion.

6 key milestones of on-premises to cloud migration

Migration is a structured process, not a single event. Each phase builds on the previous one, and the sequence matters. Here is how a well-executed migration unfolds:

Step 1: Discovery and assessment

Gaining full visibility into your current environment is the essential first step of any migration from on-premises to the cloud. This means cataloguing servers, applications, databases, storage systems, software licenses, and performance metrics. It also means mapping dependencies: which applications communicate with which databases, which services are interconnected, and what the failure impact of each system would be.

This phase often surfaces surprises—redundant systems, undocumented dependencies, or applications that haven’t been touched in years. Discovery tools like AWS Migration Hub, Azure Migrate, or Google Migration Center automate much of this inventory work and provide readiness scores for cloud migration.

To make sure nothing slips through the cracks, document the following for each workload:

• Application inventory and ownership;
• Data volumes and types (structured, unstructured, sensitive);
• Regulatory requirements;
• Current performance baselines and service-level agreements (SLAs);
• Integration points and dependencies.

Step 2: Building the business case and calculating TCO

Once you have a clear picture of your current environment, quantify the cost of staying on-premises versus migrating. On the on-premises side, a total cost of ownership (TCO) analysis should account for hardware refresh cycles, licensing, staffing, energy costs, and opportunity costs. On the cloud side, it should include cloud subscription costs, egress fees, and tooling.

This step also involves building stakeholder alignment. IT leaders, finance, and business units often have different concerns and priorities. A strong business case speaks to all of them, translating technical considerations into business outcomes and financial projections.

Step 3: Defining a strategy

With the assessment complete and the business case approved, it’s time to define a migration strategy from on-premises to the cloud for each workload. Apply the 7 Rs framework, prioritizing workloads based on complexity, business value, and risk. Group them into migration waves: start with lower-risk, lower-complexity applications to build team confidence and refine the process before tackling mission-critical systems.

At this stage, select your target cloud environment (public, hybrid, or multi-cloud) and the specific cloud provider or providers. Factor in existing enterprise agreements, your team’s technical capabilities, and the geographic availability requirements of your data.

Step 4: Conducting a proof of concept

Before full-scale on-premises to cloud migration begins, run a limited proof of concept (PoC) with a non-critical workload. The goal is to validate your migration tools, test connectivity and performance in the cloud environment, identify integration issues early, and give the team hands-on experience. A PoC rarely takes more than a few weeks but can prevent costly mistakes during the main migration.

Step 5: Executing the migration in waves

Migrate workloads in planned waves, starting with the simplest and progressing to the most complex. Each wave follows the same four-phase sequence:

1. Pre-migration: Back up data, notify stakeholders, and freeze non-critical application changes.
2. Migration: Execute the move using the appropriate tooling for the workload type (server migration, database migration, file transfer, etc.). For data-heavy migrations, consider physical transfer options (AWS Snowball, Azure Data Box) when network transfer would be impractically slow.
3. Cutover: Switch production traffic to the cloud environment, with a clear rollback plan in place.
4. Validation: Verify functionality, performance, and data integrity against pre-migration baselines.

One decision that deserves particular attention in every wave is how to handle the cutover. In on-prem to cloud migration, switching production traffic to the new environment is a high-stakes moment. The right approach varies depending on each workload’s criticality and tolerance for downtime. Three methods are commonly used:

Choosing a cutover approach

1. Blue-green deployment: Two identical environments run in parallel. Traffic switches to the cloud environment once it has been fully validated, with the on-premises environment kept as a fallback.
2. Canary migration: A small percentage of traffic is gradually shifted to the cloud environment while both systems are monitored. The share increases as confidence grows.
3. Big bang: The entire cutover happens during a planned maintenance window. This is the simplest approach and works well for smaller, lower-criticality systems where brief downtime is acceptable.

Step 6: Post-migration optimization

Migration is the beginning, but not the destination. Once workloads are running in the cloud, the focus shifts to optimization. This stage usually covers three core areas:

• Cost optimization is the most immediate priority. Rightsizing instances, setting up budget alerts, and implementing savings plans can significantly reduce ongoing spend. The key is governance: without clear ownership and monitoring policies in place, cloud costs tend to grow in the background.
• Performance tuning involves monitoring each application and adjusting configuration, architecture, or resource allocation accordingly. Behavior in the cloud often differs from on-premises due to differences in network topology, storage I/O, and compute characteristics.
• Cloud-native modernization is the longer-term opportunity. Many organizations begin with rehosting and progressively refactor workloads to take advantage of managed services, autoscaling, and cloud-native development.

Our experts note that these areas are not sequential phases with a finish line. The most successful cloud adopters treat optimization as a continuous discipline, revisiting cost, performance, and architecture regularly as workloads evolve.

Read more: Application migration to the cloud checklist to streamline your transition

Common on-premises to cloud migration challenges and how to navigate them

Even well-planned migrations encounter friction. Understanding these challenges in advance allows teams to prepare solutions and execute the migration with far less disruption.

1. Cost overruns

The cost side of on-premises to cloud migration is harder to predict than most teams expect, and easy to underestimate. Egress fees, data transfer costs, and underutilized reserved capacity are common sources of unexpected spend.

N-iX’s solution: Implement tagging policies and budget alerts before migration begins. Use native cost management tools (AWS Cost Explorer, Azure Cost Management) from day one. Assign cloud cost ownership to application teams, not just central IT. Establish a FinOps practice that reviews costs continuously rather than waiting for monthly billing surprises.

Read also: Effective cloud cost optimization: 3 essential practices to control expenses

2. Database migration complexity

Databases are among the most difficult workloads to migrate. Schema differences, version compatibility issues, data volume, and zero-downtime requirements all add complexity. A poorly executed database migration can result in data loss, corruption, or extended downtime.

N-iX’s solution: Use purpose-built database migration services (AWS Database Migration Service, Azure Database Migration Service) that support continuous replication and minimize downtime. Run source and target databases in parallel during cutover. Build a thorough validation process to verify data completeness and integrity after migration.

3. Legacy system compatibility

Applications built on older technology stacks may rely on hardware features, operating systems, or middleware that lack straightforward cloud equivalents. When moving from on-prem to the cloud, these systems can require more effort than originally scoped.

N-iX’s solution: During the assessment phase, flag applications with known compatibility risks. For each one, decide whether to refactor, replatform, retain, or retire rather than attempting a direct lift-and-shift that will likely fail. In some cases, containerization can provide a compatibility layer that allows older applications to run in cloud environments without full re-architecture.

4. Security and compliance gaps

The cloud operates on a shared responsibility model, where the cloud provider secures the infrastructure and the customer is responsible for securing what runs on top of it. Organizations migrating from on-premises sometimes underestimate how much security configuration falls on their side of that line.

N-iX’s solution: Define your security baseline before migration begins. This includes identity and access management policies, encryption requirements for data at rest and in transit, network segmentation, and audit logging. For regulated industries, map each workload’s compliance requirements to specific cloud controls. A hybrid approach, combining on-premises security for the most sensitive data with cloud-native controls elsewhere, is often the right answer.

Migration to the cloud with N-iX: A success story

Our client is a global provider of managed cloud services with offices worldwide. Their monthly equipment performance reports were generated through a largely manual process, with data scattered across siloed on-premises systems. On top of that, the process depended on a paid third-party tool, adding cost and operational complexity.

N-iX migrated the client’s MS SQL Server infrastructure to a unified data warehouse on GCP. The consolidation brought together over 70 operational data sources, 4 data warehouses, and 1 data lake into a single environment. More than 20 servers were decommissioned in the process. Our team also ensured data quality throughout by identifying and eliminating anomalies in the migrated data.

The results were significant. Automating the report generation process eliminated nearly 17,000 hours of work per year. It also removed the dependency on the third-party tool entirely and contributed to over $1M in saved costs for the client.

Explore the full case study: Automation, cloud migration, and cost optimization for a global tech company

How N-iX can facilitate your on-premises to cloud migration

N-iX brings over 23 years of software engineering experience to cloud migration projects, serving clients across finance, healthcare, logistics, technology, and other sectors. With 400 cloud engineers and 480 certifications across AWS, Azure, and Google Cloud, we bring deep, platform-specific expertise to every engagement.

Here is what we bring to your migration:

• End-to-end migration coverage: We support the full journey, from initial discovery and TCO analysis through migration execution, post-migration optimization, and cloud-native modernization. Clients have a single, experienced partner across all phases.
• Workload-level strategy: We choose a migration path for each application individually, selecting the right approach from the 7 Rs to maximize performance and cost efficiency for each workload.
• Security and compliance by design: We define security controls, IAM policies, and compliance requirements before migration begins. N-iX also holds certifications, including ISO 27001, ISO/IEC 27701:2019, PCI DSS, and CyberGRX, so you can be confident your migration meets the highest security and compliance standards.
• AI-ready infrastructure: For organizations building or scaling AI and Machine Learning capabilities, we design cloud environments that support modern data pipelines, GPU compute, and managed AI services from the outset.
• Ongoing optimization: Our teams support clients through cloud cost governance, performance tuning, DevOps, and the long-term application modernization.

Ready to assess your migration readiness? Talk to our cloud engineers about where to start.

Frequently Asked Questions

1. How long does on-premises to cloud migration take?
It depends significantly on the scope and complexity of the environment. A small organization migrating a handful of applications might complete the migration in a few weeks. A large enterprise migrating hundreds of workloads across multiple data centers could take 12-24 months, in waves.

2. How can I migrate on-premises software to scalable cloud solutions through custom development services?
Custom development services enable organizations to go beyond lift-and-shift and redesign applications to take full advantage of cloud-native architecture. N-iX helps clients assess which applications are worth modernizing and handles the engineering work required to ensure they perform well in a cloud environment.

3. What is the most efficient way to migrate from on-premises infrastructure to the cloud while minimizing downtime and data loss?
Thorough upfront planning and a phased, wave-based execution are the strongest foundations. Use continuous replication to keep environments in sync during cutover, validate data integrity at each stage, and choose the cutover method that matches each workload’s criticality.

4. What is the biggest risk in cloud migration?
Cost overruns and security misconfigurations are the most common issues. Both are preventable with proper planning, governance, and the right expertise guiding the process.

5. Can I migrate without any downtime?
For most workloads, yes, with the right approach. Techniques such as blue-green deployments and continuous replication enable cutovers with minimal or no disruption to users. Some legacy systems may require a maintenance window, but extended downtime is rarely necessary with careful planning.

References

1. The Business Value of Enhancing Microsoft Azure Projects with Practical Guidance and Resources—IDC
2. Gartner Forecasts Worldwide Public Cloud End-User Spending to Total $723 Billion in 2025—Gartner