You should have what you feel comfortable with risk-wise.
To go all in (100% stocks), you need to understand and be okay with riding out the ups and downs and understand that the market is volatile in the short term... but it does trend up over the long term. You need to know that you won't panic when the market drops 10 or 20 points in a day and start selling.
If you get that you're investing for long term (20 years from now and up) then you can look at the day to day or even year to year fluctuations as a small part of your loss/gain cycle. The market can drop suddenly, and it may take a year or two to recover. If you think you can leave things alone (and even see the drops as an investing opportunity) then you probably will be okay going all in.
If you don't think that you can be comfortable with that level of risk, then you need to figure out your level of comfort - whether that is "your age in bonds" or what - the thing is to do the research on how the market basically works, what your goals are and what you feel good about doing.
http://jlcollinsnh.com/stock-series/^ good place to start
And 30 is a good age to start learning and taking an active interest in investing. Sure 20 is even better, but you're still quite young, and I'd say that is really smart.
If I was just advising myself, then I'd say "sure, go 100% VTSAX" but then again, if you'd asked me that even 2 years ago, I'd have thought that was crazy, as I had little notion of how all of this stuff works. What a difference a bit of knowledge makes!