cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jonathan Colby <jonathan.co...@gmail.com>
Subject Re: Questions about the nodetool ring.
Date Tue, 12 Apr 2011 10:55:02 GMT
when you do a move, the node is decommissioned and bootstrapped. During the autobootstrap process
the node will not receive reads until bootstrapping is complete.  I assume during the decommission
phase the node will also be unavailable,  someone correct me if I'm wrong.

the ring distribution looks better now.

The "?" I get all the time too.   And if you run "ring" against different hosts, the question
marks probably appear in different places.   I'm not sure if it means there is a problem.
 I haven't taken those question marks too seriously.



On Apr 12, 2011, at 11:57 AM, Dikang Gu wrote:

> After the nodetool move, I got this:
> 
> [root@server3 apache-cassandra-0.7.4]# bin/nodetool -h 10.18.101.213 ring
> Address         Status State   Load            Owns    Token                        
              
>                                                        113427455640312821154458202477256070485
    
> 10.18.101.211   ?      Normal  82.31 MB        33.33%  0                            
              
> 10.18.101.212   ?      Normal  84.24 MB        33.33%  56713727820156410577229101238628035242
     
> 10.18.101.213   Up     Normal  54.44 MB        33.33%  113427455640312821154458202477256070485
> 
> Is this correct? Why is the status "?" ?
> 
> Thanks.
> 
> On Tue, Apr 12, 2011 at 5:43 PM, Dikang Gu <dikang85@gmail.com> wrote:
> The 3 nodes were added to the cluster at the same time, so I'm not sure whey the data
vary.
> 
> I calculate the tokens and get:
> node 0: 0
> node 1: 56713727820156410577229101238628035242
> node 2: 113427455640312821154458202477256070485
> 
> So I should set these tokens to the three nodes?  
> 
> And during the time I execute the nodetool move commands, can the cassandra servers serve
the front end requests at the same time? Is the data safe?
> 
> Thanks.
> 
> On Tue, Apr 12, 2011 at 5:15 PM, Jonathan Colby <jonathan.colby@gmail.com> wrote:
> This is "normal" when you just add single nodes.   When no token is assigned, the new
node takes a portion of the ring from the most heavily loaded node.    As a consequence of
this, the nodes will be out of balance.
> 
> In other words, when you double the amount nodes you would not have this problem.
> 
> The best way to rebalance the cluster is to generate new tokens and use the nodetool
move <new-token> command to rebalance the nodes, one at a time.
> 
> After rebalancing you can run "cleanup" so the nodes get rid of data they no longer are
responsible for.
> 
> links:
> 
> http://wiki.apache.org/cassandra/Operations#Range_changes
> 
> http://wiki.apache.org/cassandra/Operations#Moving_or_Removing_nodes
> 
> http://www.datastax.com/docs/0.7/operations/clustering#adding-capacity
> 
> 
> 
> On Apr 12, 2011, at 11:00 AM, Dikang Gu wrote:
> 
> > I have 3 cassandra 0.7.4 nodes in a cluster, and I get the ring stats:
> >
> > [root@yun-phy2 apache-cassandra-0.7.4]# bin/nodetool -h 192.168.1.28 -p 8090 ring
> > Address         Status State   Load            Owns    Token
> >                                                        109028275973926493413574716008500203721
> > 192.168.1.25    Up     Normal  157.25 MB       69.92%  57856537434773737201679995572503935972
> > 192.168.1.27    Up     Normal  201.71 MB       24.28%  99165710459060760249270263771474737125
> > 192.168.1.28    Up     Normal  68.12 MB        5.80%   109028275973926493413574716008500203721
> >
> > The load and owns vary on each node, is this normal?  And is there a way to balance
the three nodes?
> >
> > Thanks.
> >
> > --
> > Dikang Gu
> >
> > 0086 - 18611140205
> >
> 
> 
> 
> 
> -- 
> Dikang Gu
> 
> 0086 - 18611140205
> 
> 
> 
> 
> -- 
> Dikang Gu
> 
> 0086 - 18611140205
> 


Mime
View raw message