[MAPREDUCE-2845] Default replication level mapred.submit.replication=10 causes warnings on small clusters

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 0.20.1
• Component/s: client, distributed-cache

Environment

Cloudera CDH 2 (hadoop-0.20 0.20.1+169.127-1~lenny-cdh2)

• Tags: hdfs distributedcache replication jobjar libjars warning fsck
• Assignee: Unassigned
• Reporter: Christoph Schmitz
• Created: 16/Aug/11 06:54
• Updated: 27/Sep/11 12:25

Description

By default, the replication level for job jars, libjars and the distributed cache in general is mapred.submit.replication=10. This yields under-replication warnings for these files on small clusters (less than 10 data nodes) when using fsck ("hadoop fsck") on their HDFS.

Example on an 8-node cluster:

/tmp/hadoop/mapred/system/job_201105191458_1857/job.jar: Under replicated blk_-6996370258385460742_366223. Target Replicas is 10 but found 8 replica(s).