"owns" in nodetool

(7 posts) (3 voices)

• Started 10 months ago by ryoudelman
• Latest reply from xedin
• This topic is not a support question

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1. 

   ryoudelman
   Member

   What does the owns column mean in nodetool? I have a 2 data center ring and for data center 2 the owns shows up as 0% even though there is data there.

   Address DC Rack Status State Load Owns Token
   160688895490443163302149120176112766521
   ###.###.#.### DC1 RAC1 Up Normal 1.15 GB 5.56% 0
   ###.###.#.### DC2 RAC1 Up Normal 1.21 GB 0.00% 1
   ###.###.#.### DC1 RAC1 Up Normal 81.53 MB 5.56% 9452287970026068429538183539771339207
   ###.###.#.### DC2 RAC1 Up Normal 82.39 MB 0.00% 9452287970026068429538183539771339208
   ###.###.#.### DC1 RAC1 Up Normal 80.31 MB 5.56% 18904575940052136859076367079542678414
   ###.###.#.### DC2 RAC1 Up Normal 87.16 MB 0.00% 18904575940052136859076367079542678415
   ###.###.#.### DC1 RAC1 Up Normal 80.09 MB 5.56% 28356863910078205288614550619314017621
   ###.###.#.### DC2 RAC1 Up Normal 85.61 MB 0.00% 28356863910078205288614550619314017622
   ###.###.#.### DC1 RAC1 Up Normal 81.05 MB 5.56% 37809151880104273718152734159085356828
   ###.###.#.### DC2 RAC1 Up Normal 85.08 MB 0.00% 37809151880104273718152734159085356829
   ###.###.#.### DC1 RAC1 Up Normal 83.89 MB 5.56% 47261439850130342147690917698856696035
   ###.###.#.### DC2 RAC1 Up Normal 81.49 MB 0.00% 47261439850130342147690917698856696036
   ###.###.#.### DC1 RAC2 Up Normal 1.2 GB 5.56% 56713727820156410577229101238628035242
   ###.###.#.### DC2 RAC2 Up Normal 1.21 GB 0.00% 56713727820156410577229101238628035243
   ###.###.#.### DC1 RAC2 Up Normal 82.05 MB 5.56% 66166015790182479006767284778399374449
   ###.###.#.### DC2 RAC2 Up Normal 86.64 MB 0.00% 66166015790182479006767284778399374450
   ###.###.#.### DC1 RAC2 Up Normal 82.56 MB 5.56% 75618303760208547436305468318170713656
   ###.###.#.### DC2 RAC2 Up Normal 87.61 MB 0.00% 75618303760208547436305468318170713657
   ###.###.#.### DC1 RAC2 Up Normal 87.13 MB 5.56% 85070591730234615865843651857942052864
   ###.###.#.### DC2 RAC2 Up Normal 82.28 MB 0.00% 85070591730234615865843651857942052865
   ###.###.#.### DC1 RAC2 Up Normal 81.02 MB 5.56% 94522879700260684295381835397713392071
   ###.###.#.### DC2 RAC2 Up Normal 81.02 MB 0.00% 94522879700260684295381835397713392072
   ###.###.#.### DC1 RAC2 Up Normal 86.02 MB 5.56% 103975167670286752724920018937484731278
   ###.###.#.### DC2 RAC2 Up Normal 81.68 MB 0.00% 103975167670286752724920018937484731279
   ###.###.#.### DC1 RAC3 Up Normal 1.18 GB 5.56% 113427455640312821154458202477256070485
   ###.###.#.### DC2 RAC3 Up Normal 1.17 GB 0.00% 113427455640312821154458202477256070486
   ###.###.#.### DC1 RAC3 Up Normal 81.94 MB 5.56% 122879743610338889583996386017027409692
   ###.###.#.### DC2 RAC3 Up Normal 86.63 MB 0.00% 122879743610338889583996386017027409693
   ###.###.#.### DC1 RAC3 Up Normal 81.31 MB 5.56% 132332031580364958013534569556798748899
   ###.###.#.### DC2 RAC3 Up Normal 81.3 MB 0.00% 132332031580364958013534569556798748900
   ###.###.#.### DC1 RAC3 Up Normal 82.02 MB 5.56% 141784319550391026443072753096570088106
   ###.###.#.### DC2 RAC3 Up Normal 86.48 MB 0.00% 141784319550391026443072753096570088107
   ###.###.#.### DC1 RAC3 Up Normal 80.42 MB 5.56% 151236607520417094872610936636341427313
   ###.###.#.### DC2 RAC3 Up Normal 80.43 MB 0.00% 151236607520417094872610936636341427314
   ###.###.#.### DC1 RAC3 Up Normal 85.74 MB 5.56% 160688895490443163302149120176112766520
   ###.###.#.### DC2 RAC3 Up Normal 85.74 MB 0.00% 160688895490443163302149120176112766521

   Posted 10 months ago #
2. 

   xedin
   Member

   The "Owns" column indicates the percentage of the ring handled by node. Note: it's not an amount of "real" data on the node rather the amount (in procents) that node is responsible for comparing to all other nodes according to it's token interval. Take a look at tokens that your nodes have in DC2 - it's only off by 1 from the previous node's token, which effectively means that node is responsible for almost nothing.

   You will have to re-balance tokens of your nodes, using http://blog.milford.io/cassandra-token-calculator/ to calculate tokens and 'nodetool move' command to re-assign them.

   Additional

   https://wiki.apache.org/cassandra/Operations#Ring_management
   http://journal.paul.querna.org/articles/2010/09/24/cassandra-token-selection/

   Posted 10 months ago #
3. 

   nickmbailey
   Key Master

   Just a few extra notes in addition to what xedin said:

   Like xedin said, the ownership percentage that you are seeing there is only a calculation of percentage of tokens owned between the previous token and the current token. Which is why you see 0%. Since you have multiple datacenters, that number isn't particularly meaningful. The actual tokens that you have chosen are valid (although your ring is unbalanced, see below).

   There is a bug in JIRA for changing that column to actually display a meaningful percentage in the case of multiple datacenters. The bug has been fixed for the 1.1.1 release:

   https://issues.apache.org/jira/browse/CASSANDRA-3412

   Although the tokens you have chose are correct, your ring is unbalanced currently because you are not alternating racks with your token selection. Within each datacenter you need to alternate racks when assigning tokens in order to have a balanced ring. See:

   http://www.datastax.com/docs/1.1/initialize/token_generation#calculating-tokens-for-multiple-racks-in-a-single-data-center

   Let us know if you have any other questions.

   Posted 10 months ago #
4. 

   ryoudelman
   Member

   Thanks for the information. I will update the ring with the new tokens. This is a pre-production ring so I can drop my data. Can I just update the token in the yaml file? I think in the past I have seen it pull a "saved" token.

   Posted 10 months ago #
5. 

   nickmbailey
   Key Master

   It will only use the token in cassandra.yaml the very first time cassandra starts up. If you delete *all* cassandra data on the node '/var/lib/cassandra', then it will use the value from the conf file when you start the process again.

   Posted 10 months ago #
6. 

   ryoudelman
   Member

   Great! Thanks for all the help today.

   Posted 10 months ago #
7. 

   xedin
   Member

   In addition you can use 'nodetool move' command to set a new token to the node without deleting the data, data delete is required because token is stored into the system keyspace after the first start.

   Posted 10 months ago #

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