I'm also not a Spark user, but I have used Storm:
- Storm is significantly more mature and performant the moment.
- Storm has a better cross-language story in terms of bolt functions.
- Pretty much everything in Onyx is much more open ended. This applies to deployment, program structure, and workflow creation - and is mostly an artifact of how aggressively Onyx uses data structures.
- Onyx has a far better reach across languages in terms of its information model.
- Onyx will be adopting a tweaked version of Storm's message model next release to get on the same level of performance and reliability. We're dropping the HornetQ dependency.
- Onyx is born out of years of frustration of direct usage of Storm and Hadoop.
Performance is important: in our case, decreasing it significantly below Storm's level would not be acceptable.
Also, I watched the Strange Loop presentation and the tree model looks limiting to me: I have topologies where I need to merge information from two streams (but perhaps I haven't understood the Onyx model yet).
The tree model is being removed in 0.6.0 in favor of a vector of vectors (DAG), which allows multiple inputs. See https://github.com/MichaelDrogalis/onyx/blob/0.5.x/doc/user-... The tree model wasn't one of my better ideas.
Edit: to be clear, you can do stream joins right now in 0.5.3 with the DAG model.
I can infer two of your frustrations with Storm from the above post: that Storm was too closed, and it's information model didn't span across languages very well. If you have the time, could you elaborate on these pain points, and any others that you found?
Information models are often superior to APIs, and almost always better than DSLs. The hyper-flexibility of a data structure literal allows Onyx workflows and catalogs to be constructed at a distance, meaning on another machine, in a different language, by another program, etc. Contrast this to Storm. Topologies are written with functions, macros, and objects. These things are specific to a programming language, and make it hard to work at a distance - specifically in the browser. JavaScript is the ultimate place to be when creating specifications.
Further, the information model for an Onyx workflow has the distinct advantage that it's possible to compile other workflows (perhaps a datalog) into the workflow that Onyx understands.
See https://github.com/MichaelDrogalis/onyx/blob/0.5.x/doc/user-... for a continued explanation of why Onyx is more of an "open" concept.
