What is persistent data?

Question

Docker

I bought a course on udemy on docker. Docker captain is now talking in detail about containerization.
It turns out to be an interesting topic.
And then I came to such a topic as persistent data, and my English is simply unable to digest this topic))
Then the author of the lesson posted such links
Manage data in Docker
An introduction to immutable infrastructure
12 Fractured Apps
And then I got confused. Friends help!!!

Answer 1

What is persistent data?

This is the data that should be saved after the "death" of the container.
Unlike the "old" world of servers that set up, record data and use for years, it is customary in containers to raise a new container when deploying a new version of the program and in other cases. In general, don't rely on a running container to run after a week. Accordingly, the question arises - where to store databases and other mutable data.

Answer 2

And what is the actual question? PersistentData is a broad topic.