So (for each node) you have 4 cores available for 1 supervisor JVM, 2
worker JVMs that execute up to 5 thread each (if 40 executors are
distributed evenly over all workers. Thus, about 12 threads for 4 cores.
Or course, Storm starts a few more threads within each worker/supervisor.

If your load is not huge, this might be sufficient. However, having high
data rate, it might be problematic.

One more question: do you run a single topology in your cluster or
multiple? Storm isolates topologies for fault-tolerance reasons. Thus, a
single worker cannot process executors from different topologies. If you
run out of workers, a topology might not start up completely.

-Matthias



On 09/02/2015 09:54 PM, Nick R. Katsipoulakis wrote:
> Hello Matthias and thank you for your reply. See my answers below:
> 
> - I have a 4 supervisor nodes in my AWS cluster of m4.xlarge instances
> (4 cores per node). On top of that I have 3 more nodes for zookeeper and
> nimbus.
> - 2 worker nodes per supervisor node
> - The task number for each bolt ranges from 1 to 4 and I use 1:1 task to
> executor assignment.
> - The number of executors in total for the topology ranges from 14 to 41
> 
> Thanks,
> Nick
> 
> 2015-09-02 15:42 GMT-04:00 Matthias J. Sax <[email protected]
> <mailto:[email protected]>>:
> 
>     Without any exception/error message it is hard to tell.
> 
>     What is your cluster setup
>       - Hardware, ie, number of cores per node?
>       - How many node/supervisor are available?
>       - Configured number of workers for the topology?
>       - What is the number of task for each spout/bolt?
>       - What is the number of executors for each spout/bolt?
> 
>     -Matthias
> 
>     On 09/02/2015 08:02 PM, Nick R. Katsipoulakis wrote:
>     > Hello all,
>     >
>     > I am working on a project in which I submit a topology to my Storm
>     > cluster, but for some reason, some of my tasks do not start executing.
>     >
>     > I can see that the above is happening because every bolt I have
>     needs to
>     > connect to an external server and do a registration to a service.
>     > However, some of the bolts do not seem to connect.
>     >
>     > I have to say that the number of tasks I have is larger than the
>     number
>     > of workers of my cluster. Also, I check my worker log files, and I see
>     > that the workers that do not register, are also not writing some
>     > initialization messages I have them print in the beginning.
>     >
>     > Any idea why this is happening? Can it be because my resources are not
>     > enough to start off all of the tasks?
>     >
>     > Thank you,
>     > Nick
> 
> 
> 
> 
> -- 
> Nikolaos Romanos Katsipoulakis,
> University of Pittsburgh, PhD candidate

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