Lost task tracker reschedules all tasktracker's successful map tasks

[Leonardo Gamas <le...@jusbrasil.com.br>]

Hi,

I have a very large MapReduce Job and sometimes a TaskTracker doesn't send a
heartbeat in the preconfigured amount of time, so it's considered dead. It's
ok, but all tasks already finished by this TaskTracker are lost too, or
better explained, are rescheduled and re-executed by another TaskTracker.

This is a default behavior or i'm experiencing some bug or miss
configuration?

My reguards,

Leonardo Gamas