On 25/11/10 12:42, Grandl Robert wrote:
Thanks to you all for the explanations. So, as far as I understand, if I configure 4 map slots per node(let's say - 512 MB RAM per slot as my node has 2 GB in total) the hadoop will always try to allocate 4 slots ? Does the node report on the hearbteat that it has 4 free slots ?
But then, my question comes: what if another workload contend with hadoop workload at a moment, that means few resources available now for hadoop. Did hadoop still report he has 4 slots free and implicitly try to allocate tasks for these 4 slots ?
Do you mean other system workload? Are your machines accepting work from other places?
The JobTracker will push out work to the nodes, and remember which machines it has given work to -so won't overcommit them. If you are doing other work on the same machine, it won't know about that, and still push out jobs that will now take longer.
-steve
