Server mirror. Criteria and principles by which mirrors are made?

Question

Backup

How mirrors are transferred, by what algorithm they understand that the service is loaded and it requires a mirror. Let's say there is a Yandex service, how to understand that a mirror is needed for it? Googled, but found nothing, maybe someone will tell you, direct or recommend books.

Answer 1

The mirror is not a backup and the "backup" tag, in the context of your question, is out of place. If the server is loaded, then it needs to provide high availability - several servers processing the service; multiple channels; several data centers; data replication; load balancing. That's all. In each case, it is configured individually. Google - the architecture of high-load systems.

Answer 2

The Yandex service has horizontal scaling close to linear; mirrors are not made for such services. And in general, mirrors are not about loads.

Answer 3

How are mirrors handled?

Just like regular servers.

by what algorithm do they understand that the service is loaded and it requires a mirror.

The load on the server has nothing to do with the need to create a mirror.

Let's say there is a Yandex service, how to understand that a mirror is needed for it?

Ask the owner if the owner thinks that he needs a mirror, then it is.