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New Technologies

Cloud Migration Strategies – How to Modernise Legacy Systems

September 7, 2023
Pedro Paranhos

Time stops for no one, and the unrelenting pace of technological changes makes it seem like time is speeding up. Consider that ChatGPT completely transformed how people work and how companies deal with their technology stacks just a few months after its release.

Yet, many companies struggle to keep up with these changes. For instance, as recently as 2019, 1 in 3 companies still used Windows XP!

Ah, the nostalgia… (source)

Using outdated systems is far from a superficial issue, and there is no shortage of problems caused by this practice. Relying on legacy systems can result in poor user experience and increased business risks. In 2022, the FBI even issued a notification to warn about the dangers of outdated software in healthcare.

Legacy systems are a risk to your business

Legacy systems are not problematic simply because of their age. The problem is that they are often inflexible, costly to maintain, incompatible with other methods, and fall short of current tech standards. These systems might have served their purpose for years or even decades but now struggle to meet usage requirements.

Limited scalability, increasing maintenance costs, interoperability issues, and heightened sensitive data risks are some ways legacy systems can slow down a company’s development.

With that in mind, it’s clear that migrating from legacy systems to more modern solutions is imperative. Today, there is no better alternative for IT infrastructure than the cloud.

What is cloud computing

No matter your level of tech knowledge, I’m sure you already have some understanding of what the cloud is and how it works – at least as a user. Dropbox, Google Drive, and Microsoft Office 365 are popular cloud-based applications.

In a few words, cloud computing is the delivery of computing services such as applications, data transfer, and data storage through a network of remote servers.

The U.S. Department of Commerce’s National Institute of Standards and Technology outlines five essential characteristics of cloud computing:

  1. On-demand self-service: Users can automatically access and manage computing resources without human intervention from the service provider.
  2. Broad network access: Services can be accessed via various devices, such as mobiles, tablets, and computers, using standard network protocols.
  3. Resource pooling: Multiple users share a pool of dynamically allocated resources without knowing the exact physical location but with the ability to specify broader geographic parameters.
  4. Rapid elasticity: Resources can quickly scale up or down as needed, giving the impression of unlimited availability.
  5. Measured service: Usage is automatically monitored, optimized, and reported for transparency and billing purposes for both provider and consumer.

These characteristics indicate the main benefits of cloud computing:

  • Pay-as-you-use model: Pay only for your computing resources, reducing upfront expenses on data centers and servers.
  • Economy of scale: Cloud providers aggregate demand from multiple customers, offering lower costs than managing your infrastructure.
  • Dynamic capacity management: No more guesswork on your IT needs. Scale your resources up or down within minutes as your business demands change.
  • Increased speed and agility: Get IT resources instantly, enabling faster development and reducing time-to-market for your projects.
  • Reduced data center management: Free resources to focus on projects that add value instead of infrastructure management.
  • Global deployment ease: Quickly deploy your applications worldwide, improving customer experience with lower latency.

In short, Cloud Computing overcomes all the limitations of legacy systems!

How the cloud migration can accelerate digital transformation

Old infrastructures can’t bear the weight of today’s growing digital demands. The cloud promises increased capabilities for existing needs, such as data storage and system reliability. Also, it opens up new possibilities to incorporate the latest technologies, such as AI and microservices.

However, this goes beyond tech buzzwords. Moving to the cloud platform translates into real-world business benefits, such as substantial cost savings, improved resilience, increased operational efficiency, and innovation capability.

It’s worth noting that cloud computing services offer very high availability. Their so-called Service Level Agreements (SLA) can reach up to “multiple nines”, where each “nine” represents the decimal point in the uptime percentage. Modern cloud providers can offer an SLA of 99.999%, translating to only 26 seconds of possible unavailability per month. Remember that the lowest SLA will determine how high the SLA your system will have. It’s impossible to have an overall SLA of 99.999 when one of the components has an SLA, e.g.99.75. Also, always keep in mind how high SLA you really need. If you’re not a global company with millions of customers, it does not really make any sense to struggle for every nine there is since a short break in availability will not do you any harm. It might even go unnoticed.

Types of cloud migration strategies

There are a few ways of going from on-premises infrastructure to the cloud. This process may take considerable effort and investment depending on the size and complexity of the existing infrastructure, but it will pay off in the long run.

Here are the leading cloud migration strategies, illustrated with examples.

an image showing the most common cloud migration strategies: rehosting, refactoring, replatforming, repurchasing, retaining, and retiring
The most common cloud migration strategies: rehosting, refactoring, replatforming, repurchasing, retaining, and retiring

Rehosting (Lift-and-Shift)

Think of rehosting as relocating your applications to the cloud infrastructure with minimal alterations. It’s the digital equivalent of moving homes. It is ideal for rapid migrations but doesn’t optimize the new environment’s cloud-native features.

Refactoring a.k.a. Re-architecting

Here, the move to the cloud involves optimizing your application’s architecture and tapping into the cloud’s vast array of services and capabilities. It’s a deeper, more intensive approach but yields higher benefits.

Replatforming

In this case, you’re modernizing without rebuilding, just tweaking or upgrading your application rather than making core changes. It’s a balance between rehosting and refactoring.

Repurchasing

Sometimes, it makes sense to incorporate a plug-and-play solution that’s already set up on the cloud, leveraging SaaS platforms for operational functions. It can limit future expansion of applications, though.

Retaining

Not all legacy systems need immediate migration. In some complex cases, it might be worth staying on-premises while devising a suitable migration strategy even after deciding to migrate.

Retiring

Decommissioning deprecated, unused, bloated, or redundant systems during migration will reduce costs and streamline operations.

Cloud migration challenges

  • Data security and compliance: The migration process exposes data to potential vulnerabilities. Businesses can ensure data sanctity by implementing encryption and internal security policies and ensuring GDPR or other regional compliance.
  • Downtime and service interruptions: Downtime can harm businesses. A phased migration approach and robust rollback mechanisms can mitigate these risks and ensure successful cloud migration.
  • Cost management: From data transfer charges to unforeseen licensing costs, transparent budgeting and leveraging tools like AWS Cost Explorer or Azure Cost Management can provide financial clarity. Remember, you can save even more by paying upfront fees. Such an approach can help you save up to 70% of infrastructure costs. You can save even more if you support non-production grade environments (dev, test, etc.) and can afford stopovers. With spot instances, your fees might be peanuts, but it will be a sane choice only if you perform jobs that might be abruptly stopped.
  • Version compatibility: Sometimes systems are not 100% compatible with each other. Remember to always do your homework and check if your services will talk to each other. Also, there’s an approach that tends not to use the most recent version but the previous one. Who said the most current one will not have any bugs or holes incorporated by an accident?

Best practices for cloud migration

  • Comprehensive assessment and planning: Start with a meticulous audit. Understand interdependencies, identify potential roadblocks, and craft a tailored migration blueprint.
  • Upskilling and training: Equip your team with the skills of tomorrow. Consider certifications like AWS Cloud Practitioner or Microsoft Certified: Azure Fundamentals.
  • Continuous monitoring and optimization: Migrating isn’t the endpoint. Utilise tools like Amazon CloudWatch or Google Cloud Monitoring to continuously refine and enhance your cloud platform. You can also use external tools such as NewRelic or Zabbix.
  • Rollback strategy: Even the best plan might fail. Always remember to be prepared to go back to the previous setup. You never know when and why things might go sideways.
  • Do not optimize too quickly: You might be tempted to use all of the available services of your cloud provider but do you really need it? Sometimes the best way is to create a Proof of Concept that will be expandable instead of creating a complicated state-of-the-art system in the first place.

Future-proof your business with cloud migration

Transitioning from legacy systems to the cloud isn’t just an IT strategy; it’s a forward-looking business strategy. As modern enterprises sail into the digital horizon, the cloud is their North Star, guiding them towards innovation, resilience, and growth.

FAQ: Cloud migration strategy, cloud infrastructure

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