DataStax Enterprise 4.5

Troubleshooting

The following common problems, solutions, or workarounds have been reported about using DataStax Enterprise. Be sure to also check the Cassandra troubleshooting documentation.

Mahout Jobs that Use Lucene Not Supported

DataStax does not currently support Mahout jobs, such as built-in support for creating vectors from Lucene indexes, that use Lucene features. Attempting to run Mahout jobs that use Lucene features results in this type of error message:

Error: class org.apache.mahout.vectorizer.
DefaultAnalyzer overrides final method
tokenStream.

MX4J warning message during installation

When Cassandra loads, you may notice a message that MX4J will not load and that mx4j-tools.jar is not in the classpath.

You can ignore this message. MX4j provides an HTML and HTTP interface to JMX and is not necessary to run Cassandra. DataStax recommends using OpsCenter. It has more monitoring capabilities than MX4J.

DSE Search/Solr cannot find custom files

Open Source Solr (OSS) supports relative paths set by the <lib> property in the solrconfig.xml, but DSE Search/Solr does not. Configuring the Solr library path describes a workaround for this issue.

Subprocesses not killed when DataStax Enterprise is shut down improperly

Attention: To prevent this problem, avoid using kill 9 and shut down DataStax Enterprise as described in Stopping a DataStax Enterprise node.
If DataStax Enterprise is shut down with kill -9, you must reboot the node or manually kill any remaining sub-processes:
  • Installer-Services and Package installations:
    For example, if DataStax Enterprise 4.5 was started using sudo services dse start or sudo /etc/init.d/dse start and the main process was killed using $ kill -9 `cat /var/run/dse/dse.pid`:
    1. To view the subprocesses left behind (all DSE processes run under user "cassandra"):
      $ pgrep -c -ucassandra >/dev/null && ps -o pid,ppid,user,args `pgrep -ucassandra`
    2. To shut down the subprocesses:
      $ sudo pkill -ucassandra
  • Installer-No Services and Tarball installations:
    For example, if DataStax Enterprise 4.5 was started using sudo dse cassandra -k -t and the main process was killed using $ sudo kill -9 `cat /var/run/dse/dse.pid` or $ sudo pkill -9 -f jmxremote.port=7199:
    1. To view the subprocesses left behind:
      $ pgrep -c -f dse-4.5 >/dev/null && ps -o pid,ppid,user,args `pgrep -f dse-4.5

      All DSE processes run under user cassandra.

    2. To shut down the subprocesses:
      $ sudo pkill -f dse-4.5
Note: The kill command (SIGTERM) shuts down the subprocesses.
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