Hi
While looking into MAPREDUCE-5207 (adding defaults for
mapreduce.{map|reduce}.memory.mb), I was wondering how much headroom should
be left on top of mapred.child.java.opts (or other similar JVM opts) for
the container memory itself?
Currently, mapred.child.java.opts (per mapred-default.xml) is set to 200 MB
by default. The default for mapreduce.{map|reduce}.memory.mb is 1024 in the
code, which is significantly higher than the 200MB value.
Do we need more than 100 MB for non-JVM memory per container? If so, does
it make sense make that a config property in itself and the code to verify
all 3 values are clear enough?
Thanks
Karthik
