Splitting or Distributing very large data on PostgresQL 9.6
As @a_vlad stated, you should do have a plan. Also, for later use I would like to recommend you guys two things.

Tablespace
Citus Data (distribute data across workers)


Citus is a distributed database that combines the low-latency requests that power real-time applications with high throughput, interactive analytics on billions of events.
Citus does this by extending PostgreSQL to distribute your workload across multiple hosts, leveraging the memory, storage, and processing power of multiple machines.

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