Arun,

Inline again.

On 03-Dec-2011, at 12:39 PM, arun k wrote:
> 
> Q>Does the map/reduce task run time displayed in web GUI is decent/accurate 
> enough ?

Don't see why not. We only display what's been genuinely collected. What you 
get out of an API on the CLI is absolutely the same thing. Or perhaps I do not 
understand your question completely here - what's led you to ask this?

> Q>If i want to do find the IO rate of a task, will the task run time divided 
> by total number of FIle bytes and HDFS bytes read/written give it 
> approximately ?

Yes, that should give you a stop-watch measure. Task start -> Task end, and the 
counters the task puts up for itself.

> Q>Does the FILE Bytes read for the reduce task include the map output record 
> bytes read non-locally over network or the bytes read locally from the map 
> output records after they are copied locally ?

FILE counters are from whatever is read off a local filesystem (file:///), so 
would mean the latter. If you look again, you will notice another counter named 
"Reduce shuffle bytes" that gives you the former count - separately.

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