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https://issues.apache.org/jira/browse/CASSANDRA-3640?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Edward Capriolo updated CASSANDRA-3640:
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Description:
We can into an interesting situation. We added 2 nodes to our cluster.
Strangely these nodes were performing worse then other nodes. They had more
IOwait for example. The impact was not major but it was noticeable. Later I
determined that these Cassandra node were not in our client's list of nodes and
our clients do not auto discover. I confirmed that the hosts did not have any
scores inside it's dynamic snitch.
It is counter intuitive that a node receiving less or no direct user requests
would perform worse then others. I am not sure of the dynamic that caused this.
I understand that DSnitch is supposed to have it's own view of the world, maybe
it could share information with neighbours. Again this is more of a client
configuration issue then a direct Cassandra issue, but I found it interesting.
was:
We can into an interesting situation. We added 2 nodes to our cluster.
Strangely this node performed worse then other nodes. It had more IOwait for
example. The impact was not major but it was noticeable. Later I determined
that this Cassandra node was not in our client's list of nodes and our clients
do not auto discover. I confirmed that the host did not have any scores inside
it's dynamic snitch.
It is counter intuitive that a node receiving less or no direct user requests
would perform worse then others. I am not sure of the dynamic that caused this.
I understand that DSnitch is supposed to have it's own view of the world, maybe
it could share information with neighbours. Again this is more of a client
configuration issue then a direct Cassandra issue, but I found it quite
interesting.
> Dynamic Snitch does not compute scores if no direct reads hit the node.
> -----------------------------------------------------------------------
>
> Key: CASSANDRA-3640
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3640
> Project: Cassandra
> Issue Type: Improvement
> Affects Versions: 0.8.7
> Reporter: Edward Capriolo
> Priority: Minor
>
> We can into an interesting situation. We added 2 nodes to our cluster.
> Strangely these nodes were performing worse then other nodes. They had more
> IOwait for example. The impact was not major but it was noticeable. Later I
> determined that these Cassandra node were not in our client's list of nodes
> and our clients do not auto discover. I confirmed that the hosts did not have
> any scores inside it's dynamic snitch.
> It is counter intuitive that a node receiving less or no direct user requests
> would perform worse then others. I am not sure of the dynamic that caused
> this.
> I understand that DSnitch is supposed to have it's own view of the world,
> maybe it could share information with neighbours. Again this is more of a
> client configuration issue then a direct Cassandra issue, but I found it
> interesting.
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