How can I analyse Others data in my iPhone? My iPhone 5s currently running on iOS 9.2 has been misbehaving for a couple of months now. No matter, how much free space I give it, it slows eat it away, reducing MB by MB till I have 0 bytes free space left.

Even if I don't use the phone, it stills eat away the free space. My suspect is that an app is writing logs like a maniac. I tried syncing with iTunes thinking it might be the debug logs that gets sent for crashes etc, but it's not that either.

How do I go about getting an idea on what makes up this other data? If I know its an app (I am thinking Whatsapp since its a chat app and the only thing on my phone that keeps on running all the time), I can get rid of it.
Whatsapp might be causing the problem.delete it but if you want to backup your whatsapp contents,see if you can do that with Whatsapp itself beforehand.after removing whatsapp check the memory size and then re-install the app.