[HDFS-16277] Improve decision in AvailableSpaceBlockPlacementPolicy

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3.1
• Fix Version/s: 3.4.0, 3.3.2
• Component/s: block placement
• Labels: pull-request-available
• Hadoop Flags: Reviewed
• Assignee: guophilipse
• Reporter: guophilipse
• Created: 16/Oct/21 14:59
• Updated: 22/Oct/21 03:08
• Resolved: 22/Oct/21 02:45

Description

Hi
In product environment,we may meet two or more datanode usage reaches nealy 100%,for exampe 99.99%,98%,97%.
if we configure `AvailableSpaceBlockPlacementPolicy` , we also have the chance to choose the 99.99%(assume it is the highest usage),for we treat the two choosen datanode as the same usage if their storage usage are different within 5%.
but this is not what we want, so i suggest we can improve the decision.

Issue Links

• links to: GitHub Pull Request #3559