How to avoid problems with Perfomance, scalability and availability?

Hello,

We are building a product that will be a free social platform intended for
knowledge exchange.

We have used the following databases together to deal with our problems:

  • Users - DynamoDB
  • Content and Search - ElasticSearch (lucene)
  • Complicated machine learning processing, and custom algorithms - Redis

What do you think about it ? Which problems could we have with perfomance,
scalability and availability? What can we do to avoid it?

We will contribute with Elastic-Search creating a lot of tutorials and wiki
when we launch in our platform for free, if you are interested, please join
our community: http://www.guchex.com

Thanks,

Vinicius Melo