One possibility could be the fetch size (combined with some unexpectedly wide rows). Does lowering the result fetch size help? >From http://sqoop.apache.org/docs/1.4.7/SqoopUserGuide.html#idp774390917888 : --fetch-size Number of entries to read from database at once. Also, do you always see it fail with the YARN memory kill (due to pmem exhaustion) or do you also observe an actual java.lang.OutOfMemoryError occasionally? If it is always the former, then another suspect would be some off-heap memory use done by the JDBC driver in use, although I've not come across such a problem. ... View more

In terms of resources, five masters wouldn't strain the cluster much. The big change is that the state that lives on the master (e.g. catalog metadata, etc.) would need to be replicated with a replication factor of 5 in mind (i.e. at least 3 copies to be considered "written"). While this is possible, the recommended configuration is 3. It is the most well-tested and commonly-used. ... View more