01 - How I got started?

All naive software developers start their cloud journey with a popular cloud provider. My company began its journey with an AWS RDS setup on a c6g.xlarge instance. Things went smoothly, powered by cloud credits, until those credits inevitably ran out.

The next day, I was handed the responsibility of migrating all data from AWS to Azure. The approach I took was to use mysqldump to export the data and then load it into the Azure MySQL server using the MySQL CLI.

The Dump Command

mysqldump --host=xxxxxx.com \
          --port=3306 \
          --user=username \
          --password='xxxxxx' \
          --database database_name \
          --single-transaction \
          --routines \
          --triggers \
          --events \
          --set-gtid-purged=OFF > /data/backup.sql

The Load Command To load the dumped data into Azure, I used:

mysql --host=azure_host.com \
      --port=3306 \
      --user=username \
      --password='xxxxxx' \
      database_name < /data/backup.sql

If you want to learn more about mysqldump, I highly recommend exploring mysqldump.guru and the official documentation for a deeper dive into its features and options.

However, this migration came with numerous challenges:

1. Large Dump Size: The size of the dump was significantly large, leading to a cumbersome migration. Transferring large SQL files over the network and processing them can become a logistical nightmare.
2. Slow Process: Both dumping and loading the data turned out to be painfully slow. The performance of mysqldump for large databases can be a bottleneck, especially when moving from one cloud provider to another.
3. Replication Delays: Due to the slow process, the binlogs on AWS started to expire before I could even begin replication. This forced us to start from scratch multiple times until we figured out a workaround.
4. Network Latency: The migration involved moving data between two cloud providers, which increased the risk of network latency issues and connection drops, further adding to the migration woes.
5. Downtime: The time required to dump, transfer, and restore the data translated to a significant downtime for the application, which was unacceptable for the business.
6. Storage Space: The intermediate storage of the large dump files added pressure on available disk space, both during the export and the subsequent import.

These challenges made it clear that while mysqldump is often the first tool that comes to mind for database migrations, it is not always the best choice for large-scale databases or migrations between cloud providers.

If you’re planning a similar migration, consider alternatives such as using logical replication tools, leveraging cloud-specific database migration services, or breaking the migration into smaller, more manageable parts. These alternatives can help mitigate issues like downtime and speed up the data transfer process significantly.