cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From aaron morton <aa...@thelastpickle.com>
Subject Re: tokens and RF for multiple phases of deployment
Date Thu, 31 May 2012 09:48:23 GMT

> Could you provide some guide on how to assign the tokens in this growing deployment phases?


background http://www.datastax.com/docs/1.0/install/cluster_init#calculating-tokens-for-a-multi-data-center-cluster

Start with tokens for a 4 node cluster. Add the next 4 between between each of the ranges.
Add 8 in the new DC to have the same tokens as the first DC +1

> Also if we use the same RF (3) in both DC, and use EACH_QUORUM for write and LOCAL_QUORUM
for read, can the read also reach to the 2nd cluster?
No. It will fail if there are not enough nodes available in the first DC. 

> We'd like to keep both write and read on the same cluster.
Writes go to all replicas. Using EACH_QUORUM means the client in the first DC will be waiting
for the quorum from the second DC to ack the write. 


Cheers
-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 31/05/2012, at 3:20 AM, Chong Zhang wrote:

> Hi all,
> 
> We are planning to deploy a small cluster with 4 nodes in one DC first, and will expend
that to 8 nodes, then add another DC with 8 nodes for fail over (not active-active), so all
the traffic will go to the 1st cluster, and switch to 2nd cluster if the whole 1st cluster
is down or on maintenance. 
> 
> Could you provide some guide on how to assign the tokens in this growing deployment phases?
I looked at some docs but not very clear on how to assign tokens on the fail-over case.
> Also if we use the same RF (3) in both DC, and use EACH_QUORUM for write and LOCAL_QUORUM
for read, can the read also reach to the 2nd cluster? We'd like to keep both write and read
on the same cluster.
> 
> Thanks in advance,
> Chong


Mime
View raw message