I think you need to increase the amount of memory you give to java.
It looks like it is currently set to 256M. I upped mine to 2G. Of
course it depends on how much ram you have available.
mapred.child.java.opts is the parameter
mine is currently set to 2048M in my hadoop-site.xml file.
For performance reasons, I upped the io.sort.mb parameter. However,
if this is too close to 50% of the total memory, you will get the