FAQ
(redirected to mapreduce-user@, mapreduce-dev bcc'd)

The param you're referring to controls the maximum number of
simultaneously active mappers on a given task tracker, i.e., how many
map slots are available on that node. But a single task tracker can be
used for multiple MR jobs, so you can't look at the metrics for the
task tracker to see how many mappers ran on a job. For a single job,
the total number of mappers that are run == the number of input
splits.

Hoping that anyone who knows this stuff better than I do will reply to
correct any mistakes in my answer,
Josh
On Sun, Jun 26, 2011 at 5:16 AM, Keren Ouaknine wrote:
Hello,

I am looking for the actual number of mappers on each machine for the job. I
know how to configure the max number ("mapred.tasktracker.map.tasks.maximum"
in mapred-site.xml file), but not the actual number of mappers that were
running for a completed job.

Any idea where can I find this data?
Thanks,
Keren

--
Keren Ouaknine
Cell: +972 54 2565404
Web: www.kereno.com

Search Discussions

Related Discussions

Discussion Navigation
viewthread | post
posts ‹ prev | 1 of 1 | next ›
Discussion Overview
groupmapreduce-user @
categorieshadoop
postedJun 26, '11 at 4:54p
activeJun 26, '11 at 4:54p
posts1
users1
websitehadoop.apache.org...
irc#hadoop

1 user in discussion

Josh Wills: 1 post

People

Translate

site design / logo © 2021 Grokbase