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From Vladimir Yudovin <>
Subject Re: Error creating pool to /IP_ADDRESS33:9042 (Proving Cassandra's NO SINGLE point of failure)
Date Mon, 24 Oct 2016 16:04:36 GMT
Probably used Python driver can't restart failed operation with connection to other node. Do
you provide all three IPs to Python driver for connecting?

Best regards, Vladimir Yudovin, 

Winguzone - Hosted Cloud Cassandra
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---- On Mon, 24 Oct 2016 07:48:05 -0400Rajesh Radhakrishnan &lt;;
wrote ----



 I have  3 nodes Cassandra cluster.

 Cassandra version : dsc-cassandra-2.1.5

 Python Cassandra Driver : 2.5.1


 Running the nodes in Red Hat virtual machines.


 Node ip info: 

 Node 1: IP_ADDRESS219

 Node 2: IP_ADDRESS229

 Node 3: IP_ADDRESS230



 (IP_ADDRESS219 is masked for this email which represents something similar 123.321.123.219)



Cassandra.yaml configuration details of node1:


 listen_address: IP_ADDRESS219

 broadcast_address: commented

 rpc_address: IP_ADDRESS219

 broadcast_rpc_address : commented


 The IP address of the node is ( using the ifconfig command ) IP_ADDRESS219.


 While the cluster is up and running , when I put Node 3 (IP_ADDRESS230) down, I was able
to connect to CQLSH from IP_ADDRESS219 and IP_ADDRESS229. 


 But while I was running a Python script which just reads data from Cassandra using the cassandra-python-driver,
and when the Node 3 stops(while the script is still running I intentionally stops  node3).


 Then the script comes to a halt with OperationTimedOut: errors={}, last_host= IP_ADDRESS219.


 However if I run the script when node3 is already down, it runs and reads data.


 So during the reading operation  if any of the nodes in the cluster goes down its affects
the client operation??? Does anyone has similar situation. 


 Here we are trying to establish or prove Cassandra's always on (NO single point of failure).
 Do you know why this is happening Thank you .



Kind regards,
 Rajesh R


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