Migrating from a legacy repository to GitHub can be scary—especially when the code you rely on is at stake

Introduction

Migrating from one repository to another can be scary—especially when the code you rely on is at stake. As development needs evolve, more organizations are moving away from Subversion (SVN), GitLab, and Azure DevOps and embracing GitHub for its advanced features, improved collaboration, and seamless integrations. In this blog post, we’ll look at lessons learned when AIS migrated from SVN to GitHub and the challenges of making this switch, why GitHub is worth the effort, and how AIS can navigate even the toughest migration obstacles.

Key Problems

Suppose you only had a week to move all your belongings from your home or office to a new location. It’s likely going to be a messy process, no matter how much planning you undertake.

Boxing all your key belongings is just the start. Once everything is labeled, your valuables need to make their way into their new location and the new location needs utilities. Something simple like moving is a full-blown project with lots of touchpoints and anxiety. One missing piece can hamper your move-in and might even lead to additional costs.

Why mention all these things? Because these same principles apply when migrating your codebase to new location. Code migrations aren’t just about moving from one repository to another; they include connecting all the dots which you know of, and those which you’ll likely discover along the way.

Here’s a look at just some of the things you’ll likely need to consider as part of a migration:

• Scope & Inventory: Identify exactly what needs migrating (repos, pipelines, work items) and eliminate any obsolete elements.
• Environment Readiness: Prepare GitHub with the right configurations (org structures, permissions, Actions vs. Pipelines) to avoid rework later.
• Security & Compliance: Map existing policies to GitHub equivalents, leveraging features like GHAS for consistent governance.
• User Adoption & Training: Provide clear guidance, training, and champions so teams understand new workflows and feel confident post-migration.

If all of this isn’t enough of a challenge, imagine the need to migrate all your code within the next 12 months to meet a specific regulatory requirement deadline. Yikes.

Subversion vs. GitHub

AIS is seeing an increase in companies moving away from “legacy” repositories towards GitHub. Over the last 4-5 months AIS has performed three major migrations. Here’s why:

• GitHub receives full investment from Microsoft and new features are released monthly.
• Enterprises are striving towards innovation and that should start with your source repository.
• GitHub provides exceptional collaboration and integrated AI assistance across features.
• GitHub works well with various cloud providers.

Most of you know AWS and Azure are major players in the market and GitHub supports them both (amongst others). As more and more companies are looking at cross-cloud, or even hybrid deployments having your code in a centralized area and able to take advantage of just about any type of deployment to a host of cloud providers is very enticing to a lot of companies.

Why AIS?

AIS has a proven track when it comes to migrating from other source repositories to GitHub. Amongst the several migrations AIS has successfully performed, one required in-house developed tools to move code bases stored on servers, hosted on SVN, and even on personal computers. AIS utilized a centralized Bastion/Server, git-svn migration tool, and custom in-house scripts which collected and collated the data from all above sources combining them on the bastion and then moving the combined code to the new GitHub repository in a format understood by GitHub.

The customer needed to move to GitHub to meet new regulation requirements and advance their engineering practices. AIS’s process is to Assess, Migrate, Handover. AIS successfully identified and analyzed the various data sources, then put a plan in place to capture all the data from disparate sources. After extensive testing and back and forth with the client, we were able to successfully combine the data into a single GitHub repository including what history even though it came from different sources. When completed, the customer had a single, dependable, GitHub repository to work and access to all the GitHub goodness like Advances Security and CoPilot. We then embarked on handover and enablement with the client making sure they understood:

• Guided Walkthroughs – Helping teams understand the new repository structure.
• Branching Strategies – Establishing best practices for collaboration.
• Security & Compliance – Implementing robust security controls in GitHub.
• Training & Enablement – Ongoing support through office hours and best practices.
• Repository setup & maintenance – Creation and maintenance of repositories that store code.  

Why Migrate from Subversion?

Subversion, while still relevant does not support some of the more advanced features today’s developers require. A few examples are:

Subversion (SVN) is like a shared filing cabinet. Everyone works on files stored in a central place (a server). When you edit a file, you check it out, make changes, and then save it back to the cabinet. If two people edit the same file at the same time, it can cause conflicts that need to be manually fixed.

GitHub (which uses Git) is more like a personal workspace where everyone has their own copy of the files. You can work on changes separately, then merge them back together. If two people edit the same file, Git helps compare and combine the changes more smoothly. GitHub also has extra features like tracking issues, reviewing code, and collaborating on projects. GitHub (using Git) is more flexible, letting people work independently before combining their work. As GitHub is becoming more and more relevant in the industry, the migration process does not have to be cumbersome. AIS brings not only experience, but the technical acumen to successfully complete the migration.

Conclusion

Migrating from SVN to GitHub might seem overwhelming, but embracing GitHub unlocks modern development practices, seamless collaboration, and AI-powered capabilities that drive innovation. This post explores real-world migration challenges, solutions, and how AIS has successfully helped organizations transition smoothly, ensuring minimal disruption and maximum long-term benefits.

Now that we’ve explored why companies are migrating to GitHub and the challenges involved, the next step is understanding how to execute a smooth migration. In Part 2, we’ll break down practical steps, tools, and strategies to make your migration a success—stay tuned!.

Special Thanks to David Dracoules for contributing the majority of this blog and tackle the most difficult conversion issues.