| .. _cassandra-topology: |
| |
| cassandra-topologies.properties file |
| ================================ |
| |
| The ``PropertyFileSnitch`` :term:`snitch` option uses the ``cassandra-topologies.properties`` configuration file to determine which :term:`datacenters` and racks cluster nodes belong to. If other snitches are used, the |
| :ref:cassandra_rackdc must be used. The snitch determines network topology (proximity by rack and datacenter) so that requests are routed efficiently and allows the database to distribute replicas evenly. |
| |
| Include every node in the cluster in the properties file, defining your datacenter names as in the keyspace definition. The datacenter and rack names are case-sensitive. |
| |
| The ``cassandra-topologies.properties`` file must be copied identically to every node in the cluster. |
| |
| |
| =========================== |
| Example |
| =========================== |
| This example uses three datacenters: |
| |
| .. code-block:: bash |
| |
| # datacenter One |
| |
| 175.56.12.105=DC1:RAC1 |
| 175.50.13.200=DC1:RAC1 |
| 175.54.35.197=DC1:RAC1 |
| |
| 120.53.24.101=DC1:RAC2 |
| 120.55.16.200=DC1:RAC2 |
| 120.57.102.103=DC1:RAC2 |
| |
| # datacenter Two |
| |
| 110.56.12.120=DC2:RAC1 |
| 110.50.13.201=DC2:RAC1 |
| 110.54.35.184=DC2:RAC1 |
| |
| 50.33.23.120=DC2:RAC2 |
| 50.45.14.220=DC2:RAC2 |
| 50.17.10.203=DC2:RAC2 |
| |
| # datacenter Three |
| |
| 172.106.12.120=DC3:RAC1 |
| 172.106.12.121=DC3:RAC1 |
| 172.106.12.122=DC3:RAC1 |
| |
| # default for unknown nodes |
| default =DC3:RAC1 |
