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From "Ashic Mahtab (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-7239) Nodetool Status Reports Negative Load With VNodes Disabled
Date Tue, 29 Jul 2014 15:17:39 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-7239?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14077819#comment-14077819
] 

Ashic Mahtab commented on CASSANDRA-7239:
-----------------------------------------

I set up a low powered cluster (2GB ram, shared disks) of four nodes and put opscenter on
a fifth. All running on vmware. It's using vnodes - 256 tokens per node. I got nodetool output
shown in nodetool.png. It shows negative load on a node. At times, we even saw two nodes with
negative load. Restarting the offfending node fixed the issue. We say a slight negative node
again at a different time. It self healed though.

There's no data in the nodes (as in, the cluster doesn't have any data put in). It's been
running blank for a few days...the data in there is just cassandra's / opscenter's internal
stuff. 

The negative loads have an interesting impact on opscenter, as can be seen in opscenter.png!!

All nodes are using 2.1.0-rc4. Opscenter is v5.0.

 

> Nodetool Status Reports Negative Load With VNodes Disabled
> ----------------------------------------------------------
>
>                 Key: CASSANDRA-7239
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7239
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Tools
>         Environment: 1000 Nodes EC2 m1.large ubuntu 12.04
>            Reporter: Russell Alexander Spitzer
>            Priority: Minor
>         Attachments: nodetool.png, opscenter.png
>
>
> When I run stress on a large cluster without vnodes (num_token =1 initial token set)
The loads reported by nodetool status are negative, or become negative after stress is run.
> {code}
> UN  10.97.155.31    -447426217 bytes  1       0.2%    8d40568c-044c-4753-be26-4ab62710beba
 rack1                                                                                   
                          
> UN  10.9.132.53     -447342449 bytes  1       0.2%    58e7f255-803d-493b-a19e-58137466fb78
 rack1                                                                                   
                          
> UN  10.37.151.202   -447298672 bytes  1       0.2%    ba29b1f1-186f-45d0-9e59-6a528db8df5d
 rack1          
> {code}



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