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From arun k <arunk...@gmail.com>
Subject Capturing Map and Reduce I/O time
Date Tue, 29 Nov 2011 14:24:19 GMT
Hi guys !

I see that hadoop doesn't capture the Map task I/O time and Reduce task I/O
time and captures only map runtime  and reduce runtime. Am i right ?

By I/O time for map task i meant time taken by the map task to read the
input chunk allocated to it for processing and the time for it to write the
O/P data to the local disk.
By I/O time for Reduce task i meant time for reduce task to transfer map
O/Ps to reduce task(shuffle phase) and writing reduce O/Ps to DFS.

> What does that runtime of Map and reduce tasks mean ?
   Does it mean time taken to execute the Map method and reduce method
respectively ? (or)
   Does it mean time taken from the start of the Map/Reduce task to the
completion of the Map/Reduce task(i.e including time to read,sort ,compute
map or reduce ,merge,etc.) ?

> Which files do i need to look at and modify in Hadoop if i want to
capture the map and reduce I/O time's ?

>  If i want to capture these values for few jobs of applications like
wordcount,sort,etc. what is the best way to do ?

Can anyone guide me in this regard ?

Thanks,
Arun

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