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What is a big bang CMS migration

We will examine the concept of big bang CMS migration and how it compares to other migration options.
Jing Li

Jing Li

Aug 16, 2023
What is a big bang CMS migration

A CMS migration involves moving all content and data assets from one content management system to another. Companies typically decide they need to perform a migration if their existing CMS isn’t quite up to scratch for their current business requirements, or it could be time for a replatforming.

When it’s time to migrate, many companies opt for a big bang migration. But what is it, and are there other options available?

#What is a big bang CMS migration?

In a big bang migration, all content and data assets are migrated from the old CMS to the new CMS in one instance. Since a big bang migration happens all at once, a lengthy planning period is usually involved. For those that frequently use the CMS, like content authors and developers working on the website, there will be a cut-off time when no new content projects are being created or updated.

A typical big bang migration begins in the planning stages, where the scope, scale, and time for conducting the migration are outlined. Next, the new CMS chosen for the migration is implemented to ensure that content and data have a predetermined destination. Next comes the big bang, where migration occurs. Finally, testing and reviewing the new system are conducted to ensure everything was migrated correctly.

#Big bang vs. trickle migration

While a big bang CMS migration is a popular approach, other options are available. The trickle migration, or the phased approach, progressive migration, or strangler pattern, focuses on moving content and data assets to a new CMS piece by piece. Think of a trickle migration as a bunch of smaller migration projects rather than a single large migration project like what occurs with a big bang.

The choice of which parts of the system should be included in each phase will be outlined in the planning stages. Companies planning a phased migration will likely have a much longer planning and preparation phase than those undergoing a big bang migration.

When opting for a trickle migration, a business might start by setting up the new CMS infrastructure. After that, they can begin the phases. Phase 1 could be migrating existing themes or building a new website from scratch. Next, migrating content and data assets, followed by custom features or extensions that were originally part of the old system and necessary for the new system to function.

When choosing either a big bang or a trickle migration, you need to consider both their advantages and disadvantages:

Advantages of big bang migration

  • Less costly: Instead of maintaining your existing CMS and a new CMS simultaneously, you can perform the migration when the previous system is almost ready to be retired. This, combined with the shorter migration time, can make it less costly.
  • Less complexity: Moving from one system to another in one instance reduces complexity as your team doesn’t have to worry about managing multiple systems simultaneously.
  • Shorter wait time: Whereas other approaches might see the migration process spread out over a few months, a big bang migration can be concluded within a few hours, provided all of the prep work has been completed correctly.

Disadvantages of big bang migration

  • Rollback risk: Since a big bang migration is meant to occur in one fell swoop, it becomes harder to walk it back if anything goes wrong. Engineering teams will need to start from scratch if the migration fails, assess what went wrong, and try again.
  • Downtime required: Performing a big bang migration requires downtime for content authors and developers working with the CMS and a pause on all new projects. If everything goes well, the downtime could be handled on the weekend, but if any issues occur, that could stretch into days or weeks, resulting in lost revenue for the business.

Advantages of trickle migration

  • No downtime: Using a phased migration approach enables companies to avoid downtime when moving content assets from one CMS to another. Everything can be moved, tested, and quality checked before shutting down the older system for good.
  • Continuous learning: A CMS migration is straightforward but isn’t always easy. Since a trickle migration is done in multiple phases, engineers performing the migration can learn from any mistakes that occur. If something goes wrong in phase two, they can note it and fix the problem before it affects any other phases.
  • Less risky: The phased approach of a trickle migration is inherently less risky than if a company decides to perform a big bang migration. Breaking up the project into phases enables migration teams to deal with any issues before they become bigger. It also allows them to continue operating normally without any interruptions that could slow down time to market for new content campaigns or completely halt them.

Disadvantages of trickle migration

  • Longer time to completion: A big bang migration could occur in a few hours or days, but a trickle migration will likely take weeks or months. For companies that want to take advantage of the features of their new system, such as a headless CMS, the long wait for the migration to be complete could be problematic.
  • Complex: A trickle migration is a complex undertaking. With so many moving parts, new assets being created while the migration is already underway, and other potential challenges that might crop up during the process, a trickle migration might be a problem for some companies, even though it might be the only solution for others.
  • Expensive: When companies choose to perform a trickle migration, they need to be running two systems at the same time. Paying for multiple licenses, straining resources between two CMSs, integrating multiple systems, and coordinating a lengthy project can lead to a much higher cost when performing a phased migration. The likelihood of delays is also much higher, which can be quite costly for companies.
Big bang migrationTrickle migration
Length of time to completeShorter: A few hours or daysLonger: Weeks or months
ComplexitySimpler due to one migrationPlan out a few migration phases is needed
CostLess time required to maintain 2 systemsMore expensive due to length of time and maintenance of multiple CMSs
DowntimeRequiredNot required or negligible
FailsafesNeed to rollback to data backupContinuous learning and easier to manage errors in smaller migration projects

#Best practices for a successful big bang CMS migration

Opting for a big bang rather than a phased approach might be best for some organizations. But to avoid the potential issues that might crop up, you should consider these best practices:

Define the project scope

Outline the project scope and create a timeline and migration plan from pre-migration to final testing. Having the project scope to refer to ensures that you don’t get distracted and can avoid scope creep, adding additional time to the migration process.

Perform content mapping

When moving to a new CMS, all content assets and metadata must be moved to the new CMS; otherwise, companies could suffer from SEO and findability issues. To avoid this, it’s necessary to create an inventory of all existing content and assets in the current CMS. Also, defining the content types and fields in the new CMS and mapping them to the corresponding content in the old CMS so that data transfer issues are avoided.

Implement a new CMS system

Next, it’s time to implement the new CMS as well as any accompanying extensions and third-party services. For instance, it might be time to move a modern headless CMS.

Implement a content freeze on the old system

After implementing the new CMS, it will be time to start the final stages and prepare for migration. That starts by implementing a content freeze when any new assets can’t be created, and there’s an overall halt on any changes or updates to content in the current CMS. This ensures that there will be a smoother transition to the new CMS.

Content teams will need to pause any campaigns in progress, but provided the planning stage was done correctly; there should be no projects scheduled to be worked on once the migration has reached this period.

Back up data

After the content freeze has been implemented, teams should have a complete idea of all the content in their system and can safely back up all of the data at this point. The backup step is crucial as if anything goes wrong during the migration, the engineering team will need to access all of the data to try again.

Perform the big bang

Finally, it would be time to perform the big bang CMS migration and move all of the data and content assets to the new CMS.

Do testing on the new system

Providing the migration went smoothly, and there were no issues, it would be time to test the new CMS to ensure everything functions correctly. Also, content teams should be consulted at this stage to help inventory all content assets to ensure that everything was recovered during the migration process.

AutoWeb, one of the first internet companies in the automotive industry, wanted to upgrade its tech stack to gain better velocity and flexibility. Since they could not release digital content and provide a navigation experience that enhanced the customer journey in the way they wanted, they decided it was time to migrate from their homebrew CMS to a modern content solution.

Hygraph provided the modernized tech stack they wanted and allowed AutoWeb to change the schemas and the level of customization offered, a key consideration following a migration. Autoweb migrated to a Jamstack infrastructure and Hygraph at once. They monitored the system performance for some time to make sure everything was working and it turned out to exceed expectations. The new tech stack helped significantly boosting their organic reach and increase monetization opportunities on the website.

#Do you need a big bang CMS migration?

The choice of whether to go for a big bang or take a phased approach instead will come down to the size of your business and existing content assets. Each approach offers advantages and disadvantages over the other.

For some organizations, a big bang approach might be the easiest way to start leveraging the capabilities of a new headless CMS. For others, several sub-systems and integrations might make a big bang migration a complex undertaking.

Migrating from any platform to another isn’t a straightforward process; the same goes for a headless CMS. Get started on your migration by reading our eBook: The True Cost of CMS Migration.

Download eBook: The True Cost of CMS Migration

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Blog Author

Jing Li

Jing Li

Jing is the Content Marketing Manager at Hygraph. Besides telling compelling stories, Jing enjoys dining out and catching occasional waves on the ocean.

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