[HDFS-15278] After execute ‘-setrep 1’, make sure that blocks of the file are dispersed across different datanodes

• Type: Improvement
• Status: Patch Available
• Priority: Minor
• Resolution: Unresolved
• Component/s: namenode
• Assignee: Yang Yun
• Reporter: Yang Yun
• Created: 15/Apr/20 06:38
• Updated: 24/Dec/20 02:48

Description

After execute ‘-setrep 1’, many of blocks of the file may locate on same machine. Especially the file is written on one datanode machine. That causes data hot spots and is hard to fix if this machine is down.

Add a chosen history to make sure that blocks of the file are dispersed across different datanodes.