Q about logs in NBU

Hi,

I have searched for perfect answers about the unified and legacy logs, but i did not find one, please share your knowledge on this.

What is Legacy logs? 

what is Unified logs?

What is the purpose of Unified logs? and advantage over Legacy logs?

what is the benefits we achived using unified logging, becasue in NB v5 we toot backup without unified logs.

Regards,

-Chan