cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Dave Brosius <dbros...@mebigfatguy.com>
Subject Re: increased RF and repair, not working?
Date Fri, 27 Jul 2012 06:00:40 GMT
Quorum is defined as

(replication_factor  /  2)  +  1

therefore quorum when rf = 2 is 2! so in your case, both nodes must be up.

Really, using Quorum only starts making sense as a 'quorum' when RF=3






On 07/26/2012 10:38 PM, Yan Chunlu wrote:
> I am using Cassandra 1.0.2, have a 3 nodes cluster. the consistency 
> level of read & write are  both QUORUM.
>
> At first the RF=1, and I figured that one node down will cause the 
> cluster unusable. so I changed RF to 2, and run nodetool repair on 
> every node(actually I did it twice).
>
> After the operation I think my data should be in at least two nodes, 
> and it would be okay if one of them is down.
> But when I tried to simulate the failure, by disablegossip of one 
> node, and the cluster knows this node is down. then access data from 
> the cluster, it returned  "MaximumRetryException"(pycassa).   as my 
> experiences this is caused by "UnavailableException", which is means 
> the data it is requesting is on a node which is down.
>
> so I wonder my data might not be replicated right, what should I do? 
> thanks for the help!
>
> here is the keyspace info:
>
> /
> /
> /Keyspace: comments:/
> /  Replication Strategy: org.apache.cassandra.locator.SimpleStrategy/
> /  Durable Writes: true/
> /    Options: [replication_factor:2]/
>
>
>
> the scheme version is okay:
>
> /[default@unknown] describe cluster;/
> /Cluster Information:/
> /   Snitch: org.apache.cassandra.locator.SimpleSnitch/
> /   Partitioner: org.apache.cassandra.dht.RandomPartitioner/
> /   Schema versions: /
> /f67d0d50-b923-11e1-0000-4f7cf9240aef: [192.168.1.129, 192.168.1.40, 
> 192.168.1.50]/
>
>
>
> the loads are as below:
>
> /nodetool -h localhost ring/
> /Address         DC          Rack        Status State   Load           
>  Owns    Token /
> /                                                                      
>          113427455640312821154458202477256070484 /
> /192.168.1.50    datacenter1 rack1       Up     Normal  28.77 GB       
>  33.33%  0 /
> /192.168.1.40    datacenter1 rack1       Up     Normal  26.67 GB       
>  33.33%  56713727820156410577229101238628035242 /
> /192.168.1.129   datacenter1 rack1       Up     Normal  33.25 GB       
>  33.33%  113427455640312821154458202477256070484 /


Mime
View raw message