How to make the most fault-tolerant web application (website, database) without BGP?

Question

High availability

How to make the most fault-tolerant web application (website, database) without BGP?
How to protect yourself from falls? I understand that 100% protection is impossible. I need as much availability time as possible.
Which hosts to choose? What specs to look for? In different countries? How to reserve everything? DB, SITE?

Answer 1

To get the most fault-tolerant, you need a combination of competent software and competent infrastructure.
about a good / competent infrastructure, any cloud provider (Google Cloud, Amazon, IBM, etc.) can provide it
about software -> there are different approaches, they are mainly based on the fact that the service is distributed over a cluster (possibly different data centers), data about the state of the application are also distributed in such a way that in the event of a fall of a single node, it would be possible to automatically restore this state.
To restore the state, a couple of schemes are popular:
1. All changes in the system are logged and the state is restored from these logs (Event sourcing)
2. The state itself is stored in distributed data types (CRDT), which are self-restored from their replicas.
the rest of the schemes are already outdated (redundant redundancy, etc.).