Introduction
As the Head of Engineering at Bacancy, I’ve worked with organizations of different sizes that struggled with the same challenge: the databases were getting stuck on-premises while the rest of the business was easily being migrated to the cloud. Applications were already modernizing, workloads were scaling, yet the database remained a bottleneck.
Businesses tried different ways to solve this, and migrating to Google Cloud SQL was one of the ways that proved to be quite effective. In this article, I want to share my perspective on how to move an on-prem database to Google Cloud SQL based on real-world experience across multiple client projects.
Why Should You Migrate Your Database to Google Cloud SQL?
Before we talk about the “how”, let us understand “why” behind the move. A lot of organizations hesitate to migrate because databases are seen as risky to touch. But in practice, the risks of staying on-prem are usually greater.
- Scalability: On-prem hardware has limits. Google Cloud SQL scales up or out as workloads grow.
- High Availability: Failover and replication are built in, reducing the downtime that’s common in on-prem setups.
- Cost Management: You pay for what you use. Hardware refresh cycles, maintenance contracts, and storage upgrades stop draining the budget.
- Focus on Core Work: Engineers can spend less time patching database servers and more time building features.
On-Premise Database Migration to Cloud SQL: A Checklist to Follow
Without preparation, migrations fail or create downtime that businesses can’t afford. Being a leading database migration service provider, here’s what we prioritize at Bacancy before touching a single record:
1. Assess the Current Database
Start by understanding what you’re moving. What’s the size of the database? Which version are you running? Are there dependencies with applications, batch jobs, or third-party tools? These answers determine the best migration path.
2. Choose the Right Cloud SQL Engine
Google Cloud SQL provides support for MySQL, PostgreSQL, and SQL Server. If your on-prem database matches one of these engines, migration is straightforward. If not, you’ll need a conversion step, often handled with Database Migration Service (DMS) or third-party tools.
3. Plan for Downtime and Cutover
No migration is truly “zero-downtime.” You need to plan how much downtime is acceptable and align with stakeholders. Some teams run dual writes for a short period; others schedule a final cutover window. Setting expectations early prevents surprises.
4. Backup and Rollback Strategy
I’ve never done a database migration without a fallback plan. Even if you think your plan is full-proof, things can still go wrong. Always take full backups and keep rollback scripts ready. Confidence comes from preparation.
Top 3 Database Migration Approaches To Choose From
There’s no single way to move an on-prem database to Cloud SQL. The choice depends on size, complexity, and tolerance for downtime.
1. Using Google’s Database Migration Service (DMS)
For MySQL and PostgreSQL, DMS is the most efficient tool. It supports both homogeneous migrations (MySQL to MySQL, PostgreSQL to PostgreSQL) and schema conversion when needed. DMS handles replication, schema migration, and even ongoing data sync until cutover.
- When to use: Small to medium databases, when minimal downtime is required.
- Advantages: Automated, reliable, and cloud-native.
- Limitations: Limited to supported engines.
2. Backup and Restore
For some projects, especially with smaller databases, exporting data from on-prem and restoring it into Cloud SQL is enough. Tools like mysqldump, pg_dump, or SQL Server backups can be used.
- When to use: Small databases or test environments.
- Advantages: Simple, low-cost, quick setup.
- Limitations: Requires downtime and manual verification.
3. Continuous Replication
For larger databases or when downtime needs to be near zero, continuous replication is the best route. Data is replicated in near real time until the final switchover. This can be achieved with DMS for supported engines or third-party replication tools for others.
- When to use: Large, business-critical databases.
- Advantages: Minimal downtime, smooth cutover.
- Limitations: More setup and monitoring effort required.
If you can’t decide which approach is right for you, you can always consider taking help of database migration service provider. Their team of experts will assess your current workloads and business goals and help you make the right choice.
Process to Migrate Your On-Premise Database to Google Cloud SQL
Every engagement has nuances, but the process we follow is consistent.
1. Set Up Cloud SQL Instance
Choose the right machine type, storage, and networking configuration. Pay special attention to networking. Configure your VPC and firewall rules properly so applications can connect securely without running into latency or access issues later.
2. Schema Migration
Always move the schema first, before any data. This gives you a chance to validate compatibility, indexes, and constraints without dealing with millions of rows at the same time. It’s much easier to catch problems here than after the data is loaded.
3. Data Migration
Once the schema looks good, move the data. Depending on the size and complexity, you can use Database Migration Service, dump and restore, or replication. Whatever you choose, monitor throughput and errors closely. Long-running migrations tend to fail in small but painful ways if left unattended.
4. Testing and Validation
At this stage, don’t just trust the migration tools. Run application queries, test reporting workloads, and check for data integrity issues. Common gotchas include collation mismatches, timezone handling, or unsupported data types. This is where you find them.
5. Cutover
When you’re confident in testing, switch the applications to point to the new Cloud SQL endpoint. Have a rollback plan ready, but if earlier steps were done carefully, this step should be fairly smooth.
6. Post-Migration Optimization
The migration isn’t really over until the new system runs better than the old one. This is the time to tune queries, adjust indexes, and take advantage of Cloud SQL features like automated backups, high availability, and performance insights. These optimizations are what make the move worthwhile.
Final Thoughts
Migrating an on-prem database to Google Cloud SQL is not just about moving data. It’s about freeing engineering teams from the weight of legacy infrastructure. The path isn’t always easy, there are compatibility issues, cutover risks, and application dependencies to manage. But with the right preparation and the right tools, the payoff is significant.
In my role, I’ve seen organizations go from nightly downtime and constant storage issues to running databases that scale on demand with near-zero disruption. Google Cloud SQL makes that possible, provided the migration is approached carefully and systematically.
And, if you need to migrate more than just the databases to the Google Cloud, our Google Cloud Migration Services can support a full move to the cloud, covering applications, workloads, and infrastructure.
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