On 7/16/2015 10:46 AM, Jim.Musil wrote:
> In 5.1, we are creating a collection using the Collections API with an
> initial replicationFactor of X. This value is then stored in the state.json
> file for that collection.
>
> If I try to issue ADDREPLICA on this cluster, it throws an error saying that
> there are no live nodes for additional replicas.
>
> If I connect a new solr node to zookeeper and issue an ADDREPLICA call, the
> replica is created and no errors are thrown, but replicationFactor remains at
> X in the state.json file.
>
> Why? What does replicationFactor really mean? It seems like it's being
> honored in some cases and ignored in others.
I believe what I'm saying below is correct. Hopefully someone with more
knowledge will speak up if I'm wrong.
If you're not using a shared filesystem (which I think right now is only
HDFS), then the only time replicationFactor is used is at collection
creation time. It won't affect anything that happens later.
If you ARE using HDFS, then there is a feature called autoAddReplicas
which will detect when your replica count is below replicationFactor and
automatically add more replicas until you're back in compliance. I know
almost nothing about this feature. Here is the issue where it was added
and the page in the reference guide where the feature is mentioned:
https://issues.apache.org/jira/browse/SOLR-5656
https://cwiki.apache.org/confluence/display/solr/Running+Solr+on+HDFS
Thanks,
Shawn
