[
https://issues.apache.org/jira/browse/MAPREDUCE-2324?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13072725#comment-13072725
]
Arun C Murthy commented on MAPREDUCE-2324:
------------------------------------------
Sorry for coming in late. I'm a little worried that this is too elaborate a fix
for a very rare corner case...
For e.g. your worst case is something like 5k jobs in a 5k node cluster:
5000 * 5000 * 100bytes -> 2.5G!
Admittedly that is far-fetched, yet illustrates the (remote) risk for a rare
corner case.
Robert - how many times have you seen this?
> Job should fail if a reduce task can't be scheduled anywhere
> ------------------------------------------------------------
>
> Key: MAPREDUCE-2324
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-2324
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Affects Versions: 0.20.2, 0.20.205.0
> Reporter: Todd Lipcon
> Assignee: Robert Joseph Evans
> Fix For: 0.20.205.0
>
> Attachments: MR-2324-security-v1.txt, MR-2324-security-v2.txt,
> MR-2324-security-v3.patch
>
>
> If there's a reduce task that needs more disk space than is available on any
> mapred.local.dir in the cluster, that task will stay pending forever. For
> example, we produced this in a QA cluster by accidentally running terasort
> with one reducer - since no mapred.local.dir had 1T free, the job remained in
> pending state for several days. The reason for the "stuck" task wasn't clear
> from a user perspective until we looked at the JT logs.
> Probably better to just fail the job if a reduce task goes through all TTs
> and finds that there isn't enough space.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
