What should be hadoop.tmp.dir ?

Question

Hadoop has configuration parameter hadoop.tmp.dir which, as per documentation, is `\"A base for other temporary directories.\" I presume, this path ref

Answer 1

It's confusing, but hadoop.tmp.dir is used as the base for temporary directories locally, and also in HDFS. The document isn't great, but mapred.system.dir is set by default to "${hadoop.tmp.dir}/mapred/system", and this defines the Path on the HDFS where where the Map/Reduce framework stores system files.

If you want these to not be tied together, you can edit your mapred-site.xml such that the definition of mapred.system.dir is something that's not tied to ${hadoop.tmp.dir}