There's no silver-bullet option for "fault tolerance" in situations like this. You absolutely do *not* want to start up alternate versions of the sharded entities in this situation -- that's classic split-brain, and is the surest route to data corruption. You could create some sort of reliable-ish messaging to the entities in this situation, so that the messages will get retried after the entities are back, but as with any reliable-messaging solution, getting it right is a considerable amount of effort, and involves somewhere between "some" and "tons" of overhead. (Depending on how tolerant you're trying to be.)
This is pretty classic Akka: messaging *is* unreliable, due to situations like this and others like it. Success with Akka requires internalizing that. Any fault tolerance is typically up to the higher-level code -- if it needs reliability, it is up to the higher-level protocol (particularly at the sending end) to implement that. On Mon, Feb 27, 2017 at 12:53 PM, Andrey Ilinykh <ailin...@gmail.com> wrote: > Hello everybody! > I do some research about akka sharding. One moment is not clear for me > right now. > If some node becomes unreachable (crashed but not down, for example) all > shards which belong to this node become unreachable. Which means all > messages to these actors are dropped. > Is it correct? > If so, is it possible to implement some fault tolerance mechanism here? > > Thank you, > Andrey > > -- > >>>>>>>>>> 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 akka-user+unsubscr...@googlegroups.com. > To post to this group, send email to akka-user@googlegroups.com. > Visit this group at https://groups.google.com/group/akka-user. > For more options, visit https://groups.google.com/d/optout. > -- >>>>>>>>>> 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 akka-user+unsubscr...@googlegroups.com. To post to this group, send email to akka-user@googlegroups.com. Visit this group at https://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
