After a factory reset, what data automatically restores?

[AC Question]

After installing the 5.1 lollipop update, my Nexus 5 isn't able to restart itself. I think the only way to fix it might be to do a factory reset. However, I really don't want to lose all my data, and have no way of backing it up since I can't even turn my phone on. I heard that after a factory reset some apps automatically restore by entering your gmail account. So I wanted to ask if there's any chance my photos and music will restore too? (I use Google's default photos and music apps).
If anyone has another idea of how to keep my data or to back it up in some way that doesn't require turning the phone on, that would be excellent!
Thanks in advance

 

[belodion]

Welcome to Android Central.

Before we go any further, are you able to boot into Recovery?

Posted via the Android Central App

 

[dancing-bass]

Belondion is right - check if you can boot into recovery. There are other options available before resorting to a factory reset.

Assuming worst case, all Google apps will have their data backed up. This includes all Google Play items (apps, books, movies, music) as well as Gmail, Photos, any games that use Google Play as backup (some do, but not all) etc.

Call logs, and SMS are not backed up, nor any locally stored files. Cloud-based storage of course you can bring back (Box, Dropbox, etc) once you install the app.