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Posted to commits@cassandra.apache.org by "J. Ryan Earl (JIRA)" <ji...@apache.org> on 2013/10/10 16:51:42 UTC

[jira] [Updated] (CASSANDRA-6179) "Load" calculated in "nodetool info" is strange/inaccurate in JBOD setups

     [ https://issues.apache.org/jira/browse/CASSANDRA-6179?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

J. Ryan Earl updated CASSANDRA-6179:
------------------------------------

    Environment: JBOD layouts  (was: JBOD disk layouts)

> "Load" calculated in "nodetool info" is strange/inaccurate in JBOD setups
> -------------------------------------------------------------------------
>
>                 Key: CASSANDRA-6179
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6179
>             Project: Cassandra
>          Issue Type: Bug
>         Environment: JBOD layouts
>            Reporter: J. Ryan Earl
>
> We recently noticed that the storage capacity on Cassandra nodes using JBOD layout was returning what looks close to the average data volume size, instead of the sum of all JBOD data volumes.  It's not exactly an average and I haven't had time to dig into the code to see what it's really doing, it's like some sort of sample of the JBOD volumes sizes.
> So looking at the JBOD volumes we see:
> {noformat}
> [jre@cassandra2 ~]$ df -h
> Filesystem            Size  Used Avail Use% Mounted on
> [...]
> /dev/sdc1             1.1T  9.4G  1.1T   1% /data/1
> /dev/sdd1             1.1T  9.2G  1.1T   1% /data/2
> /dev/sde1             1.1T   11G  1.1T   1% /data/3
> /dev/sdf1             1.1T   11G  1.1T   1% /data/4
> /dev/sdg1             1.1T  9.2G  1.1T   1% /data/5
> /dev/sdh1             1.1T   11G  1.1T   1% /data/6
> /dev/sdi1             1.1T  9.8G  1.1T   1% /data/7
> {noformat}
> Looking at 'nodetool info' we see:
> {noformat}
> [jre@cassandra2 ~]$ nodetool info
> Token            : (invoke with -T/--tokens to see all 256 tokens)
> ID               : 631f0be3-ce52-4eb9-b48b-069fbfdf0a97
> Gossip active    : true
> Thrift active    : true
> Native Transport active: true
> Load             : 10.57 GB
> {noformat}
> So there are 7 disks in a JBOD configuration in this example, the sum should be closer to 70G for each node.  Maybe we're misinterpreting what this value should be, but things like OpsCenter appear to use this "load" value as the size of data on the local node, which I expect to be the sum of JBOD volumes.



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