"All my life is music."
Translation:Вся моя жизнь — это музыка.
I guess you could say that one means "Music is all my life" and the other means "All my life is music", but in English I'd say those are two perfectly acceptable ways of saying exactly the same thing and either ought to be accepted as a translation of the Russian phrase here. Is it not the same in Russian?
The difference is in wording, not in meaning. You can say it both ways in Russian AND in English, so I think there is no reason to accept both word orders. A user is supposed to "translate" what's written, not what might have been written instead, had the author chosen to express themselves differently.
Sounds odd to my ear. Целый (whole, in one piece) is used for "entire" in contexts where you imply a huge, enormous amount, which is unusually large—for example, "He spent in this village his all, entire life". You may render this as «Он целую жизнь прожил в этой деревне», though всю also works.
Целый день is also a combination very popular in speech (when you talk about something that happens all day long or about spending all day on something).
However, when you say something like "all my life is love/work/music/science", it sounds out of place. I guess, we do not parse it an action performed on your entire life.