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From "Tan Jun" <tanjun_2...@163.com>
Subject About slots of tasktracker and munber of map taskers
Date Mon, 12 Dec 2011 03:18:44 GMT
I dont really understand the meaning of the sentences in "The Definitive Guide"(page 155):

Tasktrackers have a fixed number of slots for map tasks and for reduce tasks: for example,
a tasktracker may be able to run two map tasks and two reduce tasks simultaneously.
(The precise number depends on the number of cores and the amount of
memory on the tasktracker; see “Memory” on page 254.)

Does that mean the number of slots is fixed and the number of maps run simultaneously is set
by user?
If that, how do the number of cores and memory decide the number of slots?

Tan Jun
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