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https://issues.apache.org/jira/browse/HADOOP-4766?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12658802#action_12658802
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amar_kamat edited comment on HADOOP-4766 at 12/23/08 1:14 AM:
--------------------------------------------------------------
I tried running 5 sleep jobs with 100,000 maps (1 sec wait) on 200 nodes back
to back. Here are the runtimes
||run-no||time||
|1|25min 58sec|
|2|26min 14sec|
|3|26min 19sec|
|4|25min 53sec|
Note that the total memory used after running 9 sleep jobs (100,000 maps with 1
sec wait) back to back (few were killed) was ~384MB. Note that the cluster is
configured to keep 0 jobs in memory (using the
[patch|https://issues.apache.org/jira/secure/attachment/12395497/HADOOP-4766-v1.patch])
and 5 min tracker-expiry-interval. This experiment was to prove that
eventually the job leaves the JobTracker's memory.
was (Author: amar_kamat):
I tried running 5 sleep jobs with 100000 maps on 200 nodes back to back.
Here are the runtimes
||run-no||time||
|1|25min 58sec|
|1|25min 58sec|
|1|25min 58sec|
|1|25min 58sec|
> Hadoop performance degrades significantly as more and more jobs complete
> ------------------------------------------------------------------------
>
> Key: HADOOP-4766
> URL: https://issues.apache.org/jira/browse/HADOOP-4766
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.18.2, 0.19.0
> Reporter: Runping Qi
> Assignee: Amar Kamat
> Priority: Blocker
> Fix For: 0.18.3, 0.19.1, 0.20.0
>
> Attachments: HADOOP-4766-v1.patch, map_scheduling_rate.txt
>
>
> When I ran the gridmix 2 benchmark load on a fresh cluster of 500 nodes with
> hadoop trunk,
> the gridmix load, consisting of 202 map/reduce jobs of various sizes,
> completed in 32 minutes.
> Then I ran the same set of the jobs on the same cluster, yhey completed in 43
> minutes.
> When I ran them the third times, it took (almost) forever --- the job tracker
> became non-responsive.
> The job tracker's heap size was set to 2GB.
> The cluster is configured to keep up to 500 jobs in memory.
> The job tracker kept one cpu busy all the time. Look like it was due to GC.
> I believe the release 0.18/0.19 have the similar behavior.
> I believe 0.18 and 0.18 also have the similar behavior.
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