Jobtracker is out of memory with 100,000 dummy map tasks job

[심탁길]

 
Hi all
 
Recently I tried 100,000 dummy map tasks job on the 100ea node(2GB, Dual Core, 
64Bit machine, Version: 0.16.4) cluster
 
Map task does nothing but sleeping one minute
 
I found that Jobtracker(1GB Heap) consumes about 650MB of heap memory when the 
job is 50% done.
 
After all, the job failed at the 90% of progress because Jobtracker hanged 
up(?) due to out of memory.
 
how do you handle this kind of issue? 
 
another related issue:
 
while the above job was being processed, I clicked on the "Pending" on 
jobdatails.jsp of web UI
 
then, Jobtracker consumed 100% of CPU. and 100% CPU status lasted a couple of 
minutes