Hello Roland. Many thanks for your answer. Very clear point of view.
Many thanks for your help! Regards, Eduardo. El jueves, 8 de mayo de 2014 10:24:11 UTC+2, Akka Team escribió: > > Hi Eduardo, > > there are several parts which will have to play together in relation to > your requirement of avoiding delay during a failover: > > - first you need to decide that you want to fail over, which means > that the backup needs to determine that it has to become active > - then you need to get the backup in shape (bringing it up to the > persisted level of the primary before the failure > - then you need to switch the responsibility for persisting state > changes to the backup > > The first one will probably take some time, typically of the order of > several seconds; if you make it faster then you risk failing over too > eagerly due to some GC pauses, in which case the primary node will not know > that it should deactivate itself when it comes back from the freezer. > > In general having multiple sources of “truth” is a hard problem that can > only be solved by mutual exclusion or merging. This is a tough problem that > admittedly is not fully solved yet, and the Akka Persistence toolbox is > also lacking in this regard (e.g. merging the log streams from multiple > “equivalent” processors into a single journal or supporting an exclusion > scheme for disabling the old processor after a failover). > > What you can currently do is to rely on the sharding infrastructure to > provide only exactly one copy of an entity at any given point in time and > reduce failover latency by judicious use of snapshots. > > Regards, > > Roland > > > > On Mon, May 5, 2014 at 11:35 AM, Eduardo Fernandes > <[email protected]<javascript:> > > wrote: > >> Hi all. >> >> I'm trying a hot swap between an active processor and a backup one, in >> line with the >> this<https://www.assembla.com/spaces/akka/tickets/3938#/activity/ticket:> >> ticket, >> to avoid delay while swapping huge actors. >> >> I'm thinking about manually sending my commands to two different actors >> in a active/passive fashion. In case of node failure I'd like to point out >> to the passive instance, avoiding startup delay. I'm thinking about having >> two sharding regions and then, after node failure and using a particular >> sharding strategy, point out to the node where the passive object is. Maybe >> the hotswap (as decribed >> here<http://doc.akka.io/docs/akka/snapshot/java/untyped-actors.html#untypedactor-hotswap>) >> >> can be used to deviate the commands to passive actor. In the meanwhile the >> standard Akka persistence scheme is being used to re-initiate the original >> actor that could be used later after a new node failure. >> >> Do you think that this approach is feasible or maybe there is another >> simpler way to achieve this behavior? >> >> Many thanks for your help. >> >> Eduardo. >> >> -- >> >>>>>>>>>> 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] <javascript:>. >> To post to this group, send email to [email protected]<javascript:> >> . >> Visit this group at http://groups.google.com/group/akka-user. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Akka Team > Typesafe - The software stack for applications that scale > Blog: letitcrash.com > Twitter: @akkateam > -- >>>>>>>>>> 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.
