Hi Durga Sir,
I have gone through your video and I have one question.
You told that Secondary name node merge the fsimage and Edit logs and pass to namenode.
So how often it happens- whether it happens every hour then for every hour namenode go in safemode and fsimage get updated.
Or it happen only when namenode restart. I have doubt here.
If it happens every hour then how it goes on safemode and come out, and how the running job works.