The number of slots defines the number of worker JVM a supervisor can
start. And a single worker JVM only executes code of a single topology
(to isolate topologies for fault-tolerance reasons).

Thus, you need to have a least a single worker for each topology in your
cluster (ie, sum of all slots over all supervisors)---assuming a
topology uses only a single worker.

It is not required to have a slot per supervisor per topology per se.

However, take into account the parameter "numberOfWorkers" that you can
set per topology. This is the maximum number of slots a topology can
occupy. If less workers are present, the topology will run using the
available once. If you want all your topologies to be able to use this
max number of workers, you need to have enough slots in your cluster.
Otherwise, the first topologies will occupy as much workers as they are
allowed, and for later deployed topologies not slots might be left over.

-Matthias


On 04/28/2016 03:35 AM, I PVP wrote:
> Hi everyone,
> 
> Do I need to have one slot(supervisor.slots.ports:) at the storm.yaml
>  for each Topology? 
> 
> What is the impact of having a number of Slots smaller than the number
> of Topologies ?  
> 
> So far I am understanding that  the impact is that some topologies will
> never run. I have 12 Topologies and  they all only run fine when the
> number of slots is equal or higher  to the number of Topologies. When
> the number os Slots is smaller some topologies never start and uptime
>  for these topologies is blank.
> 
> Thanks
> 
> -- 
> IPVP
> 

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