You can store most things in an ETS table, or mnesia if you want something distributed. But a lot of times, your customers or end users will end up abusing a sy

You can store most things in an ETS table, or mnesia if you want something distributed. But a lot of times, your customers or end users will end up abusing a system that was meant for fast read/write access and small data sizes. Then people like me get paged at 4 AM in the morning because ERTS happily consumes all available memory. You should plan to use Ecto and an RDBMS for most use-cases.