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From Dominik Petrovic <dominik.petro...@mail.ru.INVALID>
Subject Re[4]: Modify keyspace replication strategy and rebalance the nodes
Date Thu, 14 Sep 2017 17:36:04 GMT
@jeff,
I'm using 3 availability zones, during the life of the cluster we lost nodes, retired others
and we end up having some of the data written/replicated on a single availability zone. We
saw it with nodetool getendpoints.
Regards 


>Thursday, September 14, 2017 9:23 AM -07:00 from Jeff Jirsa <jjirsa@gmail.com>:
>
>With one datacenter/region, what did you discover in an outage you think you'll solve
with network topology strategy? It should be equivalent for a single D.C. 
>
>-- 
>Jeff Jirsa
>
>
>On Sep 14, 2017, at 8:47 AM, Dominik Petrovic < dominik.petrovic@mail.ru.INVALID >
wrote:
>
>>Thank you for the replies!
>>
>>@jeff my current cluster details are:
>>1 datacenter
>>40 nodes, with vnodes=256
>>RF=3
>>What is your advice? is it a production cluster, so I need to be very careful about
it.
>>Regards
>>
>>
>>>Thu, 14 Sep 2017 -2:47:52 -0700 from Jeff Jirsa < jjirsa@gmail.com >:
>>>
>>>The token distribution isn't going to change - the way Cassandra maps replicas
will change. 
>>>
>>>How many data centers/regions will you have when you're done? What's your RF now?
You definitely need to run repair before you ALTER, but you've got a bit of a race here between
the repairs and the ALTER, which you MAY be able to work around if we know more about your
cluster.
>>>
>>>How many nodes
>>>How many regions
>>>How many replicas per region when you're done?
>>>
>>>
>>>
>>>
>>>-- 
>>>Jeff Jirsa
>>>
>>>
>>>On Sep 13, 2017, at 2:04 PM, Dominik Petrovic < dominik.petrovic@mail.ru.INVALID
> wrote:
>>>
>>>>Dear community,
>>>>I'd like to receive additional info on how to modify a keyspace replication
strategy.
>>>>
>>>>My Cassandra cluster is on AWS, Cassandra 2.1.15 using vnodes, the cluster's
snitch is configured to Ec2Snitch, but the keyspace the developers created has replication
class SimpleStrategy = 3.
>>>>
>>>>During an outage last week we realized the discrepancy between the configuration
and we would now fix the issue using NetworkTopologyStrategy. 
>>>>
>>>>What are the suggested steps to perform?
>>>>For Cassandra 2.1 I found only this doc:  http://docs.datastax.com/en/cassandra/2.1/cassandra/operations/opsChangeKSStrategy.html
 
>>>>that does not mention anything about repairing the cluster
>>>>
>>>>For Cassandra 3 I found this other doc:  https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsChangeKSStrategy.html
 
>>>>That involves also the cluster repair operation.
>>>>
>>>>On a test cluster I tried the steps for Cassandra 2.1 but the token distribution in
the ring didn't change so I'm assuming that wasn't the right think to do.
>>>>I also perform a nodetool repair -pr but nothing changed as well.
>>>>Some advice?
>>>>
>>>>-- 
>>>>Dominik Petrovic
>>
>>-- 
>>Dominik Petrovic


-- 
Dominik Petrovic
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