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From "Brandon Williams (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-7239) Nodetool Status Reports Negative Load With VNodes Disabled
Date Fri, 29 Aug 2014 17:21:53 GMT


Brandon Williams commented on CASSANDRA-7239:

It appears the root of the problem here is that we have a serious bookkeeping problem.  We
only increment totalDiskSpaceUsed in DataTracker.replaceFlushed, which is to say that we only
count flushed memtables.  This means if you do a compaction, even if the result isn't negative,
your reported load is completely wrong:

root@bw-2:/srv/cassandra# du -sh /var/lib/cassandra/data/Keyspace1/
163M    /var/lib/cassandra/data/Keyspace1/
root@bw-2:/srv/cassandra# bin/nodetool status
Note: Ownership information does not include topology; for complete information, specify a
Datacenter: datacenter1
|/ State=Normal/Leaving/Joining/Moving
--  Address        Load       Tokens  Owns    Host ID                               Rack
UN  33.16 MB   256     100.0%  ac9b6dd7-233e-4cd5-a7e0-bc9564871704  rack1

(33MB because that's the size this machine likes to flush at, and there was one flush after
the compaction.)  It looks like we need to increment somewhere in compaction as well, probably
CompactionTask completes.  This area isn't my forte, though.

> Nodetool Status Reports Negative Load With VNodes Disabled
> ----------------------------------------------------------
>                 Key: CASSANDRA-7239
>                 URL:
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Tools
>         Environment: 1000 Nodes EC2 m1.large ubuntu 12.04
>            Reporter: Russell Alexander Spitzer
>            Priority: Minor
>             Fix For: 2.1.0
>         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    -447426217 bytes  1       0.2%    8d40568c-044c-4753-be26-4ab62710beba
> UN     -447342449 bytes  1       0.2%    58e7f255-803d-493b-a19e-58137466fb78
> UN   -447298672 bytes  1       0.2%    ba29b1f1-186f-45d0-9e59-6a528db8df5d
> {code}

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