Hi Mateusz, the words “current state” mean something purely local in a distributed system, in Akka it means only within a single actor. This means that you will need to feed your decision inputs into one actor which will then make the decisions (the output). You can make that resilient by replicating it either in space or time: spatial replication means running multiple of these actors in lockstep, receiving the same inputs and hopefully producing the same outputs. The latter needs to be monitored and deviating replicas need to be shut down and replaced (using e.g. majority voting). Temporal replication means to make the actor persistent (e.g. using event-sourcing from the Akka Persistence module) so that it can continue after a failure.
The second option is simpler to implement but recovery takes longer, which seems the right choice in your case. Regards, Roland 2 jun 2014 kl. 09:57 skrev 09goral <[email protected]>: > Hi All :) > > I am new here and new to designing distributed systems. My goal is to build a > product that connects to different web services, gathers data and depending > on this new infromation makes other calls to these services. You can imagine > it as trading platform but not high frequency trading where every second > matters. I have been thinking about how this system should be designed, how > to distribute work so monitoring and supervision would be easiest. I will > post my architecture design soon but the main reason I am here is how to > build a decision point in my system. I have been thinking that I need one > place where all information is gathered, so called brain of the system, that > has all knowledge about current system state. This one node would make > decision which of available services should post a trade. My main concern is > that it caneasily become single point of failure and lead to taking down all > system. > > Has any of you experience with such problems? What can you suggest? > > Thank you :) > Mateusz > > -- > >>>>>>>>>> Read the docs: http://akka.io/docs/ > >>>>>>>>>> Check the FAQ: > >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html > >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user > --- > You received this message because you are subscribed to the Google Groups > "Akka User List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/akka-user. > For more options, visit https://groups.google.com/d/optout. Dr. Roland Kuhn Akka Tech Lead Typesafe – Reactive apps on the JVM. twitter: @rolandkuhn -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
