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POHUnavailableException:May not be enough replicas present to handle consistency level
 

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    <p>I am using Cassandra 1.2.4 on my machine (windows 7).</p> <p>I have got 3 nodes in my DC1, which is on my machine. I am only using one DC (my machine). I did keep replication factor=2 and "HConsistencyLevel.ONE". However, when one of the nodes is down, and I attempt to read or write to DB, I get the error - "May not be enough replicas present to handle consistency level.". I am under the impression that when we keep the consistency level as "ONE" and even if one node is up, the write/read should happen without errors. But I get this error. Could someone correct me as what I was doing wrong here. I did search in google but didn't get much help about this error although this error is quite relevant. I want to make the read/write happen in the event of node failure. Below is my code.</p> <pre><code>String keySpaceName="kspace"; String clusterName="Test Cluster"; String columFamilyName="ktable"; String host="127.0.0.1:9160,127.0.0.2:9161,127.0.0.3:9162"; int replicationFactor=2; CassandraHostConfigurator cassandraHostConfigurator = new CassandraHostConfigurator(host); Cluster cluster = HFactory.getOrCreateCluster(clusterName,cassandraHostConfigurator); KeyspaceDefinition keyspaceDef = cluster.describeKeyspace(keySpaceName); ConfigurableConsistencyLevel configurableConsistencyLevel = new ConfigurableConsistencyLevel(); Map&lt;String, HConsistencyLevel&gt; clmap = new HashMap&lt;String, HConsistencyLevel&gt;(); // Define CL.ONE for ColumnFamily "ktable" clmap.put(columFamilyName, HConsistencyLevel.ONE); configurableConsistencyLevel.setReadCfConsistencyLevels(clmap); configurableConsistencyLevel.setWriteCfConsistencyLevels(clmap); if(keyspaceDef==null) { KeyspaceDefinition newKeyspace = HFactory.createKeyspaceDefinition( keySpaceName, ThriftKsDef.DEF_STRATEGY_CLASS,replicationFactor, null); cluster.addKeyspace(newKeyspace, true); } Keyspace keyspace = HFactory.createKeyspace(keySpaceName, cluster, configurableConsistencyLevel); StringSerializer ss = StringSerializer.get(); ColumnFamilyTemplate&lt;String, String&gt; cft = new ThriftColumnFamilyTemplate&lt;String, String&gt;(keyspace, columFamilyName, ss, ss); ColumnFamilyUpdater&lt;String, String&gt; updater = cft.createUpdater("xkey"); UUID uid = new UUID(); updater.setValue("id",Long.toString(uid.getClockSeqAndNode()),ss); updater.setValue("name", "Catherine", ss); updater.setValue("state", "GA", ss); cft.update(updater); </code></pre>
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    1. USKiran
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    1. COCan you paste the schema output from 'show schema;' in cassandra-cli? Is it possible the keyspace was created before your script ran with replication factor 1?
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    2. CO@Richard - Thank you for the reply. I created the keyspace with replication factor "2" before the code execution. create keyspace kspace with placement_strategy = 'SimpleStrategy' and strategy_options = {replication_factor : 2} and durable_writes = true; My question was - even in the event of node failure, how can I write/read data successfully to cassandra. Any help would be highly appreciated. Regards, Kiran.
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    3. COAny suggestions on my issue would be highly appreciated.
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