alt Hacker News> I've never met an engineering team that used Riak
I was part of a recent cloud migration. Part of on-prem (though unfortunately not migrated by my team) were this very first Riak Cluster I saw in production.
The engineering team used it as "kind of S3" for images, with 3 to 5 PHP scripts providing an interface to Riak and imageMagic. It seemed to me like a good abstraction and I think the migration to S3 was mostly painless.
Other than that I only had contact with Riak at university around 15 years ago, when we tested cluster setups of several NoSQL databases and tried to manually introduce faults to see if they could heal. Riak passed our test at that time, MongoDB didn't.
I've talked to some people who use Riak as an S3 and reported that their reasoning for sticking to it is 2 to 4 orders of magnitude faster than S3. This blew my mind, but then they showed me 20ms response times from their Riak cluster and 2-second response times from S3. Now, I think these aren't standard, and in my experience, I'd say Riak is more like a single order of magnitude faster.