Ask HN: What to expect in an established startups onsite SRE interviews?

I'm about to fly SFO for a big YC startup's SRE interview and really nervous about it. I feel and know that I'm good at what I do, I built, managed, designed, architected many working and fulfilling projects, environments. Consulted inhouse and outhouse.

But this process is terrifying me. Whiteboard coding, 5 - 6 engineers and hours of interviews with Linux fundamentals, concurrency, scaling and more. I'm not sure if that's constructive.

I'm efficient with coding but I do not memorize. I always use reference materials, even for simple parameter orders. I know complexity but never ever need to do memorized analysis. Never know if some algorithm is n log n or n^2 from heart but have the grasp and educated guess for how it would do under pressure. Also can lookup or test easily. I use my memory for problem solving and reference counting so I know where to look anything.

I'm not sure If I will do well in this situation.

So What should I expect from this? If you were in my shoes how would you proceed?