architecture - SaaS database design - Multiple Databases? Split?

Question

I've seen SaaS applications hosted in many different ways. Is it a good idea to split features and modules across multiple databases? For example, putting things like the User table on one DB and feature/app specific tables on another DB and perhaps other commonly shared tables in another DB?

Answer 1

Start with one database. Split data/functionality when project requires it.

Here is what we can learn from LinkedIn:

• A single database does not work
• Referential integrity will not be possible
• Any data loss is a problem
• Caching is good even when it's modestly effective
• Never underestimate growth trajectory

Source:

LinkedIn architecture

LinkedIn communication architecture