Thanks Sameer for your answer.
I am using two DCs DC1 , DC2 with both having one node each, my straegy_options values are DC1:1,DC2:1  I am not sure what my RF should be , should it be 1 or 2?
Please Advise
Thanks
Anurag

On Wed, May 11, 2011 at 5:27 PM, Sameer Farooqui <cassandralabs@gmail.com> wrote:
Anurag,

The Cassandra ring spans datacenters, so you can't use token 0 on both nodes. Cassandra’s ring is from 0 to 2**127 in size.

Try assigning one node the token of 0 and the second node 8.50705917 × 10^37 (input this as a single long number).

To add a new keyspace in 0.8, run this from the CLI:
create keyspace KEYSPACENAME with placement_strategy = org.apache.Cassandra.locator.NetworkTopologyStrategy' and strategy_options = [{replication_factor:2}];

If using 0.7, run "help create keyspace;" from the CLI and it'll show you the correct syntax.


More info on tokens:
http://journal.paul.querna.org/articles/2010/09/24/cassandra-token-selection/
http://wiki.apache.org/cassandra/Operations#Token_selection


On Wed, May 11, 2011 at 4:58 PM, Anurag Gujral <anurag.gujral@gmail.com> wrote:
Hi All,
             I am testing network topology strategy in cassandra I am using two nodes , one node each in different data center.
Since the nodes are in different dc I assigned token 0 to both the nodes.
I added both the nodes as seeds in the cassandra.yaml and  I am  using properyfilesnitch as endpoint snitch where I have specified the colo details.

I started first node then I when I restarted second node I got an error that token "0" is already being used.Why am I getting this error.

Second Question: I already have cassandra running in two different data centers I want to add a new keyspace which uses networkTopology strategy
in the light of above errors how can I accomplish this.


Thanks
Anurag