exact meaning of maxShardsPerNode

[Bernd Fehling <be...@uni-bielefeld.de>]

Hi list,

what is the exact meaning and usage of "maxShardsPerNode"?

Say, I have 3 Server with 2 Java instances each (Port 8983 and 7574)
and a replicationFactor of 2.

With one collection on each Port (collA=8983, collB=7574) and
3 shards per collection, I see:

(all port 8983)
collA --> shard 1 --> core_node 2 , core_node 5
       --> shard 2 --> core_node 1 , core_node 6
       --> shard 3 --> core_node 3 , core_node 4

(all port 7574)
collB --> shard 1 --> core_node 1 , core_node 4
       --> shard 2 --> core_node 3 , core_node 6
       --> shard 3 --> core_node 2 , core_node 5

What is the current "maxShardsPerNode"?

Does maxShardsPerNode mean per instance or per collection or per core_node?

What I have seen by setting maxShardsPerNode to 3 and adding replicas was
that new replicas with port 7574 were added to collA (port 8983).
How can this be?

The part "Node" in "maxShardsPerNode" is somewhat confusing to me.

Regards
Bernd

Re: exact meaning of maxShardsPerNode

[Shawn Heisey <ap...@elyograg.org>]

On 3/2/22 04:24, Bernd Fehling wrote:
> what is the exact meaning and usage of "maxShardsPerNode"?
>
> Say, I have 3 Server with 2 Java instances each (Port 8983 and 7574)
> and a replicationFactor of 2. 

It SHOULD mean shards per Solr instance, with no ability in the code to 
know that multiple instances are running on the same machine.

I think there is a possibility that maxShardsPerNode is broken, and I 
think I even saw an issue that completely removes the parameter, but I 
don't know if I am remembering correctly, and if I am, I don't recall 
whether the removal had actually been done.

Thanks,
Shawn