is it forgotten to document how to set SPARK_WORKER_DIR?

[Nan Zhu]

Hi, all  

I’m trying to change my worker dir to a mounted disk with larger space

but I found that no document telling me how to do this,  

I have to check the source code and found the following lines

 if (System.getenv("SPARK_WORKER_DIR") != null) {
    workDir = System.getenv("SPARK_WORKER_DIR")
  }


is it forgotten to be documented?

Best,  

--  
Nan Zhu