To give some context, I am from a small start up (4 team members) and we work in the education space.
We've developed an e-learning platform that several schools are already using. We currently have around 20k page requests to the platform coming in a day.
We want to start gathering every bit of data we can about our users so that we can start doing some data analysis and learning from our data.
I've spent the last couple of weeks learning up about Cassandra as I think it will be a great solution for gathering all this user data and being able to read it quickly. I've also learned that to do things like SUM and AVG queries, I'll have to use something like Hadoop to be able to run mapreduce operations on the data as Cassandra doesn't allow for this sort of querying.
Our current MySQL data base is VERY small (150mb or so). With that in mind, is it worth going down the Cassandra road yet?
I'm beginning to wonder if I'm looking too far ahead, so far as scalability is concerned. An option I have been considering is to simplify things and begin with ElasticSearch, storing all our user event data and allowing us to easily search it without having to use something like Hadoop.
The main question: Is Cassandra going to be suitable for us yet at such a small scale? Or should we consider a simpler noSQL store like ElasticSearch?