[HDFS-4804] WARN when users set the block balanced preference percent below 0.5 or above 1.0

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0.4-alpha
• Fix Version/s: 2.1.0-beta
• Hadoop Flags: Reviewed
• Assignee: Stephen Chu
• Reporter: Stephen Chu
• Created: 07/May/13 15:11
• Updated: 27/Aug/13 22:07
• Resolved: 07/May/13 21:43

Description

With the new feature added in HDFS-1804 (Add a new block-volume device choosing policy that looks at free space), it'd be useful to have a WARN log if the operator sets dfs.datanode.fsdataset.volume.choosing.balanced-space-preference-percent to a value greater than 1.0. This might happen if the operator mistakenly assumes that this setting takes in a percentage number from 0.0-100.0, while the setting actually takes a range 0.0-1.0.

Also, it'd be useful to WARN in the case that value is set below 0.5, which would cause disks with less free space to get more block allocations.