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From Zhong Li <...@voxeo.com>
Subject Re: Understanding Virtual Nodes on Cassandra 1.2
Date Wed, 30 Jan 2013 17:46:35 GMT
> You add a physical node and that in turn adds num_token tokens to the ring.

No, I am talking about Virtual Nodes with order preserving partitioner. For an existing host
with multiple tokens setting list on cassandra.inital_token. After initial bootstrapping,
the host will not aware changes of cassandra.inital_token. If I want add a new token( virtual
node), I have to rebuild the host with new token list.

My question is if there is way to add a virtual nodes without rebuild it?

Thanks,

On Jan 30, 2013, at 10:21 AM, Manu Zhang wrote:

> On Wed 30 Jan 2013 02:29:27 AM CST, Zhong Li wrote:
>> One more question, can I add a virtual node manually without reboot
>> and rebuild a host data?
>> 
>> I checked nodetool command, there is no option to add a node.
>> 
>> Thanks.
>> 
>> Zhong
>> 
>> 
>> On Jan 29, 2013, at 11:09 AM, Zhong Li wrote:
>> 
>>> I was misunderstood this
>>> http://www.datastax.com/dev/blog/virtual-nodes-in-cassandra-1-2 ,
>>> especially
>>> "If you want to get started with vnodes on a fresh cluster, however,
>>> that is fairly straightforward. Just don’t set the
>>> |initial_token| parameter in your|conf/cassandra.yaml| and instead
>>> enable the |num_tokens| parameter. A good default value for this is 256"
>>> 
>>> Also I couldn't find document about set multiple tokens
>>> for cassandra.inital_token
>>> 
>>> Anyway, I just tested, it does work to set  comma separated list of
>>> tokens.
>>> 
>>> Thanks,
>>> 
>>> Zhong
>>> 
>>> 
>>> On Jan 29, 2013, at 3:06 AM, aaron morton wrote:
>>> 
>>>>> After I searched some document on Datastax website and some old
>>>>> ticket, seems that it works for random partitioner only, and leaves
>>>>> order preserved partitioner out of the luck.
>>>> Links ?
>>>> 
>>>>>  or allow add Virtual Nodes manually?
>>>> If not looked into it but there is a cassandra.inital_token startup
>>>> param that takes a comma separated list of tokens for the node.
>>>> 
>>>> There also appears to be support for the ordered partitions to
>>>> generate random tokens.
>>>> 
>>>> But you would still have the problem of having to balance your row
>>>> keys around the token space.
>>>> 
>>>> Cheers
>>>> -----------------
>>>> Aaron Morton
>>>> Freelance Cassandra Developer
>>>> New Zealand
>>>> 
>>>> @aaronmorton
>>>> http://www.thelastpickle.com <http://www.thelastpickle.com/>
>>>> 
>>>> On 29/01/2013, at 10:31 AM, Zhong Li <zli@voxeo.com
>>>> <mailto:zli@voxeo.com>> wrote:
>>>> 
>>>>> Hi All,
>>>>> 
>>>>> Virtual Nodes is great feature. After I searched some document on
>>>>> Datastax website and some old ticket, seems that it works for
>>>>> random partitioner only, and leaves order preserved partitioner out
>>>>> of the luck. I may misunderstand, please correct me. if it doesn't
>>>>> love order preserved partitioner, would be possible to add support
>>>>> multiple initial_token(s) for  order preserved partitioner  or
>>>>> allow add Virtual Nodes manually?
>>>>> 
>>>>> Thanks,
>>>>> 
>>>>> Zhong
>>>> 
>>> 
>> 
> 
> You add a physical node and that in turn adds num_token tokens to the ring.


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