Databases in modern infrastructure.
WHAT CHANGES
Storage must persist outside the container Configuration is supplied rather than edited Upgrades mean replacing the image
WHAT TO NEVER DO
Store data inside the container itself.
WHY
Removing the container removes the data.
WHAT TO USE INSTEAD
A volume, mapped to persistent storage.
WHAT TO VERIFY
That the volume is actually where you think.
WHY
A misconfigured mount silently writes into the container.
WHAT PERFORMANCE CONSIDERATIONS APPLY
Storage layer overhead Memory limits applied to the container Network between application and database
WHAT TO SET
Explicit memory limits, and matching database configuration.
WHY BOTH
A database configured for more memory than its container allows is terminated.
WHAT TO BE CAREFUL WITH
Default configurations in official images, which suit development Automatic restarts masking repeated crashes
WHAT TO PLAN
Backups, which are exactly as necessary as anywhere else.
WHY THAT NEEDS SAYING
Containerised databases are frequently treated as disposable, and then are not.
WHEN TO PREFER A MANAGED SERVICE
When you do not want to operate any of this.
WHEN TO PREFER A PLAIN SERVER
When simplicity and predictability matter more than orchestration.
