[HDFS-3647] Backport HDFS-2868 (Add number of active transfer threads to the DataNode status) to branch-1

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.20.2
• Fix Version/s: 1.2.0
• Component/s: datanode
• Hadoop Flags: Reviewed
• Assignee: Harsh J
• Reporter: Steve Hoffman
• Created: 12/Jul/12 18:45
• Updated: 15/May/13 05:16
• Resolved: 14/Jul/12 01:41

Description

Not sure if this is in a newer version of Hadoop, but in CDH3u3 it isn't there.

There is a lot of mystery surrounding how large to set dfs.datanode.max.xcievers. Most people say to just up it to 4096, but given that exceeding this will cause an HBase RegionServer shutdown (see Lars' blog post here: http://www.larsgeorge.com/2012/03/hadoop-hbase-and-xceivers.html), it would be nice if we could expose the current count via the built-in metrics framework (most likely under dfs). In this way we could watch it to see if we have it set too high, too low, time to bump it up, etc.

Thoughts?

Issue Links

• is superceded by: HDFS-2868 Add number of active transfer threads to the DataNode status