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From Vasileios Vlachos <vasileiosvlac...@gmail.com>
Subject Re: Adding datacenter for move to vnodes
Date Thu, 06 Feb 2014 22:16:35 GMT
Hello,

My question is why would you need another DC to migrate to Vnodes? How
about decommissioning each node in turn, changing the cassandra.yaml
accordingly, delete the data and bring the node back in the cluster and let
it bootstrap from the others?

We did that recently with our demo cluster. Is that wrong in any way? The
only think to take into consideration is the disk space I think. We are not
using amazon, but I am not sure how would that be different for this
particular issue.

Thanks,

Bill
On 6 Feb 2014 16:34, "Alain RODRIGUEZ" <arodrime@gmail.com> wrote:

> Glad it helps.
>
> Good luck with this.
>
> Cheers,
>
> Alain
>
>
> 2014-02-06 17:30 GMT+01:00 Katriel Traum <katriel@google.com>:
>
>> Thank you Alain! That was exactly what I was looking for. I was worried
>> I'd have to do a rolling restart to change the snitch.
>>
>> Katriel
>>
>>
>>
>> On Thu, Feb 6, 2014 at 1:10 PM, Alain RODRIGUEZ <arodrime@gmail.com>wrote:
>>
>>> Hi, we did this exact same operation here too, with no issue.
>>>
>>> Contrary to Paulo we did not modify our snitch.
>>>
>>> We simply added a "dc_suffix" in the property in
>>> cassandra-rackdc.properties conf file for nodes in the new cluster :
>>>
>>> # Add a suffix to a datacenter name. Used by the Ec2Snitch and
>>> Ec2MultiRegionSnitch
>>>
>>> # to append a string to the EC2 region name.
>>>
>>> dc_suffix=-xl
>>>
>>> So our new cluster DC is basically : eu-west-xl
>>>
>>> I think this is less risky, at least it is easier to do.
>>>
>>> Hope this help.
>>>
>>>
>>> 2014-02-02 11:42 GMT+01:00 Paulo Ricardo Motta Gomes <
>>> paulo.motta@chaordicsystems.com>:
>>>
>>> We had a similar situation and what we did was first migrate the 1.1
>>>> cluster to GossipingPropertyFileSnitch, making sure that for each node we
>>>> specified the correct availability zone as the rack in
>>>> the cassandra-rackdc.properties. In this way,
>>>> the GossipingPropertyFileSnitch is equivalent to the EC2MultiRegionSnitch,
>>>> so the data location does not change and no repair is needed afterwards.
>>>> So, if your nodes are located in the us-east-1e AZ, your cassandra-rackdc.properties
>>>> should look like:
>>>>
>>>> dc=us-east
>>>> rack=1e
>>>>
>>>> After this step is complete on all nodes, then you can add a new
>>>> datacenter specifying different dc and rack on the
>>>> cassandra-rackdc.properties of the new DC. Make sure you upgrade your
>>>> initial datacenter to 1.2 before adding a new datacenter with vnodes
>>>> enabled (of course).
>>>>
>>>> Cheers
>>>>
>>>>
>>>> On Sun, Feb 2, 2014 at 6:37 AM, Katriel Traum <katriel@google.com>wrote:
>>>>
>>>>> Hello list.
>>>>>
>>>>> I'm upgrading a 1.1 cassandra cluster to 1.2(.13).
>>>>> I've read here and in other places that the best way to migrate to
>>>>> vnodes is to add a new DC, with the same amount of nodes, and run rebuild
>>>>> on each of them.
>>>>> However, I'm faced with the fact that I'm using EC2MultiRegion snitch,
>>>>> which automagically creates the DC and RACK.
>>>>>
>>>>> Any ideas how I can go about adding a new DC with this kind of setup?
>>>>> I need these new machines to be in the same EC2 Region as the current
ones,
>>>>> so adding to a new Region is not an option.
>>>>>
>>>>> TIA,
>>>>> Katriel
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> *Paulo Motta*
>>>>
>>>> Chaordic | *Platform*
>>>> *www.chaordic.com.br <http://www.chaordic.com.br/>*
>>>> +55 48 3232.3200
>>>> +55 83 9690-1314
>>>>
>>>
>>>
>>
>

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