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The "HadoopSupport" page has been changed by GabrieleRenzi. http://wiki.apache.org/cassandra/HadoopSupport?action=diff&rev1=7&rev2=8 -------------------------------------------------- Cassandra's splits are location-aware (this is the nature of the Hadoop InputSplit design). Cassandra gives hadoop a list of locations with each split of data, and Hadoop tries to schedule jobs on instances near that data, which in practice means you should have Hadoop instances on each of your Cassandra machines. + Releases before 0.6.2/0.7 are affected by a small resource leak that may cause jobs to fail (connections are not released properly, causing a resource leak). Depending on your local setup you may hit this issue, and workaround it by raising the limit of open file descriptors for the process (e.g. in linux/bash using `ulimit -n 32000`). + The error will be reported on the hadoop job side as a thrift TimedOutException. + + If you are testing the integration against a single node and you obtain some failures, this may be normal: you are probably overloading the single machine, which may again result in timeout errors. You can workaround it by reducing the number of concurrent tasks + {{{ + Configuration conf = job.getConfiguration(); + conf.setInt("mapred.tasktracker.map.tasks.maximum",1); + }}} + + Also, you may reduce the size in rows of the batch you are reading from cassandra + {{{ + ConfigHelper.setRangeBatchSize(job.getConfiguration(), 1000); + }}} +
