Database Reference
In-Depth Information
Preparing Cassandra for Hadoop
The nodes that have Hadoop on them need to have virtual nodes disabled. So, if you have a
Cassandra cluster, you may want to split it into two data centers. You will need to configure
a proper endpoint snitch (such as
PropertyFileSnitch
) to separate the two data cen-
ters. The data centers need not actually be in different data centers. To disable the virtual
node, change the following in
cassandra.yaml
:
1. Uncomment
initial_token
, set to an appropriate value within the data center
or leave it to a default value, say,
1
.
2. Set
num_tokens
to
1
.
If you are trying to divide an existing cluster into two parts, one for data storage (the nor-
mal vnode-enabled data center for data storage) and another for analytics (the ones that
have vnode disabled and stays along with Hadoop), make sure, in analytics data center, you
decommission those nodes then clean data from data directories and restart them after mak-
ing the previously mentioned changes. This is the same as adding new nodes to the cluster.
Disabling vnode in an existing running cluster is not advised.
