cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From aaron morton <aa...@thelastpickle.com>
Subject Re: changing replication strategy and effects on replica nodes
Date Fri, 01 Apr 2011 13:37:39 GMT
You may do, if a node is no longer a replica for a token range. Which would be similar to reducing
the RF.

nodetool cleanup is the thing to run after you have repaired to remove data a node should
no longer have. 

Aaron

On 1 Apr 2011, at 23:10, Jonathan Colby wrote:

> Hi Aaron -  Yes, I've read the part about changing the replication factor on a running
cluster.  I've even done it without a problem.  My real point of my question was ....
> 
>> do you now have unused replica data on the "old" replica nodes that you need to clean
up manually?
> 
> any insight would be appreciated.
> 
> On Apr 1, 2011, at 1:45 PM, aaron morton wrote:
> 
>> See the section on Replication here http://wiki.apache.org/cassandra/Operations#Replication
It talks about how to change the RF and then says you can do the same when change the placement
strategy. 
>> 
>> It can be done, but is a little messy. 
>> 
>> Depending on your setup it may also be possible to copy / move the nodes manually
by moving sstable files.  
>> 
>> I've not done it myself, are you able to run a test ?
>> 
>> Hope that helps. 
>> Aaron
>> 
>> On 1 Apr 2011, at 02:04, Jonathan Colby wrote:
>> 
>>> 
>>> From my understanding of replica copies,  cassandra picks which nodes to replicate
the data based on replication strategy, and those same "replica partner" nodes are always
used according to token ring distribution.
>>> 
>>> If you change the replication strategy,  does cassandra pick new nodes to replicate
to?   (for example if you went from simple strategy to a networkTopology strategy where copies
are to be sent to another datacenter)
>>> 
>>> If so,  do you now have unused replica data on the "old" replica nodes that you
need to clean up manually?
>> 
> 


Mime
View raw message