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https://issues.apache.org/jira/browse/JCR-3588?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Cody Burleson updated JCR-3588:
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Attachment: Screen Shot 2013-05-03 at 4.14.52 PM.png
Also peculiar - see Screen Shot 2013-05-03 at 4.14. In these charts, from
positions 1-36/37ish, there was no user load on one of the nodes. But
jackrabbit is keeping up with the revisions happening on the node that still
has load. There's no user load, but it's still taking 30-40% of the CPU. You
can see that the java heap is showing a lot of activity for doing this revision
catch-up work. At position 36-37, we added the load back onto the node. So,
this may be a little bit unrelated, but could be we're not sure. It just seems
to be more memory and processor intensive than expected for a node that has no
user load.
> Response time higher on Node1 with load when Node2 has no load
> --------------------------------------------------------------
>
> Key: JCR-3588
> URL: https://issues.apache.org/jira/browse/JCR-3588
> Project: Jackrabbit Content Repository
> Issue Type: Bug
> Components: clustering
> Affects Versions: 2.4.3
> Environment: CentOS 6.4 running WebSphere Application Server
> 7.0.0.19. Jackrabbit cluster configuration with 2 WAS servers. Repository on
> DB2 9.7.
> Reporter: Cody Burleson
> Attachments: JackrabbitCluster-ResponseTime.png, Node1repository.xml,
> Node2repository.xml, Screen Shot 2013-05-03 at 3.49.52 PM.png, Screen Shot
> 2013-05-03 at 4.04.32 PM.png, Screen Shot 2013-05-03 at 4.14.52 PM.png
>
>
> In our performance analysis, we are seeing a strange effect, which we does
> not make sense to us. It may or may not be a defect, but we need to
> understand why the effect occurs. In a 2 node cluster, we can run a certain
> load (reading and writing) directly on Node1 and an equivalent load (reading
> and writing on Node2). We measure the response time on both nodes, and it's
> less than 2 seconds. If we stop the load to one of the servers, the response
> time on the other server triples (with no additional load). See attached
> image "JackrabbitCluster-ResponseTime.png". The left side of the report shows
> when only one node (Node1) has load and Node2 has no load. In this case, the
> response times on Node1 are at about 6 seconds. Then, on the right side of
> the report, we add an equivalent load to Node2 and then the response times on
> Node1 drop to 2 seconds. So, the load on Node1 was always consistent, yet
> ADDING load to Node2 actually improves response time on Node1. Logically, it
> doesn't make much sense, eh? Someone, please, at least help us understand why
> this may be happening.
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