Hi,

I would like to know what redundant power supply is?

What’s the difference between normal power supply?

There is basically no difference, its a power supply that is only energised if the primary one has failed, or is about to fail, to prevent the server going offline through power loss.

A good host who offers redundant power supplies will also plug that second power supply into a "B" power source which should be on a separate UPS, separate power panel and separate generator. That way they can have a complete failure on one side of the house and still keep you up.

Quite handy, in my opinion!

Does that mean that you need 1 normal power supply and
1redundant power supply in the server or you only need
1 redundant power supply?

I'm not sure I understand the exact wording of your question, but, for example, if you are buying a dedicated server and it says it has a redundant power supply, in my opinion I would take that to mean that the server has two power supplies. That, of course, doesn't necessarily mean it is connected to a separate grid. You may want to ask them about that.

Does that help?

thanks for answers :)