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Posted to user@cassandra.apache.org by Badrjan <ba...@tuta.io> on 2015/11/26 10:02:49 UTC
Change the rack of a server
So I have a 8 node cluster and I would like to change the rack of one node.
How should I do that?
B.
Re: Change the rack of a server
Posted by Badrjan <ba...@tuta.io>.
Thanks everybody for the suggestions. We are using vnodes, 1 datacenter. So
far it was all in 1 rack.
The reason for this is that we are breaking each 46 processor physical
machine to 4 docker containers with cassandra in them. Each C* will have a
separate ssd disk. Via doing this we want to achieve faster repairs. Each
physical machine will be a separate rack so that data will be replicated to
different physical machines (RF=3).B.
27. Nov 2015 04:50 by jack.krupansky@gmail.com:
> Right, and I also meant to refer to the anti-pattern doc related to racks:>
> http://docs.datastax.com/en/cassandra/2.0/cassandra/architecture/architecturePlanningAntiPatterns_c.html
>
> Although that doc seems to discourage rack selection entirely when in fact
> people should try to have replicas placed in separate racks since a lot of
> failures tend to be due to power, cooling, and network switching at the
> rack level (or so I have heard but have no personal experience.)
> -- Jack Krupansky
> On Thu, Nov 26, 2015 at 7:41 PM, Paulo Motta <> pauloricardomg@gmail.com> >
> wrote:
>
>> Changing the rack of a live node is discouraged, since the ring ranges the
>> node is responsible for will change, meaning the node will not own part
>> of the data for its new ranges and other nodes may not have some of its
>> current data.
>>
>> It will be a forbidden operation in the upcoming versions of Cassandra,
>> since it has caused trouble before, see >>
>> https://issues.apache.org/jira/browse/CASSANDRA-10242>> for more
>> background. The safest thing is to decommission the node and bootstrap the
>> node again in a new rack, as Jack suggested.
>>
>> 2015-11-26 14:40 GMT-08:00 Jack Krupansky <>> jack.krupansky@gmail.com>>
>> >:
>>
>>> What RF are you using? How many data centers? What rack configuration are
>>> you currently using/ Are you in fact using a rack-aware network topology
>>> partitioner?
>>> Specifically, what are you attempting to accomplish - why change the rack
>>> at all? Not that changing the rack is necessarily bad, just to clarify
>>> your objective.
>>> See:>>>
>>> http://docs.datastax.com/en/cassandra/2.0/cassandra/architecture/architectureDataDistributeReplication_c.html
>>>
>>> You may just have to bootstrap the new node with the proper rack and then
>>> run repair on the nodes which formerly held replicas of the old node.
>>> Or, you may have to run a full repair for all nodes of the cluster:>>>
>>> http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/opsMoveNodeRack.html
>>>
>>>
>>> -- Jack Krupansky
>>> On Thu, Nov 26, 2015 at 4:02 AM, Badrjan <>>> badrjan@tuta.io>>> > wrote:
>>>
>>>> >>>> So I have a 8 node cluster and I would like to change the
>>>> rack of one node. How should I do that?
>>>> B.>>>>
>>>
>>>
>>
>>
>
>
Re: Change the rack of a server
Posted by Jack Krupansky <ja...@gmail.com>.
Right, and I also meant to refer to the anti-pattern doc related to racks:
http://docs.datastax.com/en/cassandra/2.0/cassandra/architecture/architecturePlanningAntiPatterns_c.html
Although that doc seems to discourage rack selection entirely when in fact
people should try to have replicas placed in separate racks since a lot of
failures tend to be due to power, cooling, and network switching at the
rack level (or so I have heard but have no personal experience.)
-- Jack Krupansky
On Thu, Nov 26, 2015 at 7:41 PM, Paulo Motta <pa...@gmail.com>
wrote:
> Changing the rack of a live node is discouraged, since the ring ranges the
> node is responsible for will change, meaning the node will not own part of
> the data for its new ranges and other nodes may not have some of its
> current data.
>
> It will be a forbidden operation in the upcoming versions of Cassandra,
> since it has caused trouble before, see
> https://issues.apache.org/jira/browse/CASSANDRA-10242 for more
> background. The safest thing is to decommission the node and bootstrap the
> node again in a new rack, as Jack suggested.
>
> 2015-11-26 14:40 GMT-08:00 Jack Krupansky <ja...@gmail.com>:
>
>> What RF are you using? How many data centers? What rack configuration are
>> you currently using/ Are you in fact using a rack-aware network topology
>> partitioner?
>>
>> Specifically, what are you attempting to accomplish - why change the rack
>> at all? Not that changing the rack is necessarily bad, just to clarify your
>> objective.
>>
>> See:
>>
>> http://docs.datastax.com/en/cassandra/2.0/cassandra/architecture/architectureDataDistributeReplication_c.html
>>
>> You may just have to bootstrap the new node with the proper rack and then
>> run repair on the nodes which formerly held replicas of the old node.
>>
>> Or, you may have to run a full repair for all nodes of the cluster:
>>
>> http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/opsMoveNodeRack.html
>>
>>
>> -- Jack Krupansky
>>
>> On Thu, Nov 26, 2015 at 4:02 AM, Badrjan <ba...@tuta.io> wrote:
>>
>>> So I have a 8 node cluster and I would like to change the rack of one
>>> node. How should I do that?
>>>
>>> B.
>>>
>>
>>
>
Re: Change the rack of a server
Posted by Paulo Motta <pa...@gmail.com>.
Changing the rack of a live node is discouraged, since the ring ranges the
node is responsible for will change, meaning the node will not own part of
the data for its new ranges and other nodes may not have some of its
current data.
It will be a forbidden operation in the upcoming versions of Cassandra,
since it has caused trouble before, see
https://issues.apache.org/jira/browse/CASSANDRA-10242 for more background.
The safest thing is to decommission the node and bootstrap the node again
in a new rack, as Jack suggested.
2015-11-26 14:40 GMT-08:00 Jack Krupansky <ja...@gmail.com>:
> What RF are you using? How many data centers? What rack configuration are
> you currently using/ Are you in fact using a rack-aware network topology
> partitioner?
>
> Specifically, what are you attempting to accomplish - why change the rack
> at all? Not that changing the rack is necessarily bad, just to clarify your
> objective.
>
> See:
>
> http://docs.datastax.com/en/cassandra/2.0/cassandra/architecture/architectureDataDistributeReplication_c.html
>
> You may just have to bootstrap the new node with the proper rack and then
> run repair on the nodes which formerly held replicas of the old node.
>
> Or, you may have to run a full repair for all nodes of the cluster:
>
> http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/opsMoveNodeRack.html
>
>
> -- Jack Krupansky
>
> On Thu, Nov 26, 2015 at 4:02 AM, Badrjan <ba...@tuta.io> wrote:
>
>> So I have a 8 node cluster and I would like to change the rack of one
>> node. How should I do that?
>>
>> B.
>>
>
>
Re: Change the rack of a server
Posted by Jack Krupansky <ja...@gmail.com>.
What RF are you using? How many data centers? What rack configuration are
you currently using/ Are you in fact using a rack-aware network topology
partitioner?
Specifically, what are you attempting to accomplish - why change the rack
at all? Not that changing the rack is necessarily bad, just to clarify your
objective.
See:
http://docs.datastax.com/en/cassandra/2.0/cassandra/architecture/architectureDataDistributeReplication_c.html
You may just have to bootstrap the new node with the proper rack and then
run repair on the nodes which formerly held replicas of the old node.
Or, you may have to run a full repair for all nodes of the cluster:
http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/opsMoveNodeRack.html
-- Jack Krupansky
On Thu, Nov 26, 2015 at 4:02 AM, Badrjan <ba...@tuta.io> wrote:
> So I have a 8 node cluster and I would like to change the rack of one
> node. How should I do that?
>
> B.
>