[HDFS-3512] Delay in scanning blocks at DN side when there are huge number of blocks

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 2.0.0-alpha
• Component/s: datanode
• Labels: BB2015-05-TBR
• Assignee: amith
• Reporter: suja s
• Created: 06/Jun/12 04:30
• Updated: 11/May/15 12:06
• Resolved: 11/May/15 12:06

Description

Block scanner maintains the full list of blocks at DN side in a map and there is no differentiation between the blocks which are already scanned and the ones not scanend. For every check (ie every 5 secs) it will pick one block and scan. There are chances that it chooses a block which is already scanned which leads to further delay in scanning of blcoks which are yet to be scanned.