Snowplow is great. Super scalable and they have instructions on how to host everything on your own AWS infrastructure.

+ 1 for snowplow. We been using it for more than a year now with high traffic sites and it's working great.

What do you use as a front-end?

Why not for low volume sites?

Well it takes lots of time to setup + needs a few extra server like event collector, log cleanup and enrich, data loading and database server.