Are there tickets/documents explain how data be replicated on Virtual Nodes? If there are multiple tokens on one physical host, may a chance two or more tokens chosen by replication strategy located on same host? If move/remove/add a token   
manually, does Cassandra Engine validate the case?

Thanks.


On Jan 30, 2013, at 12:46 PM, Zhong Li wrote:

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 donít 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.