[HDFS-10916] Switch from "raw" to "system" xattr namespace for erasure coding policy

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha1
• Fix Version/s: 3.0.0-alpha2
• Component/s: erasure-coding
• Target Version/s: 3.0.0-alpha2
• Hadoop Flags: Incompatible change

Release Note

EC policy is now stored in the "system" extended attribute namespace rather than "raw". This means the EC policy extended attribute is no longer directly accessible by users or preserved across a distcp that preserves raw extended attributes.

Users can instead use HdfsAdmin#setErasureCodingPolicy and HdfsAdmin#getErasureCodingPolicy to set and get the EC policy for a path.

• Assignee: Andrew Wang
• Reporter: Andrew Wang
• Created: 27/Sep/16 22:27
• Updated: 11/Oct/16 21:15
• Resolved: 11/Oct/16 17:06

Description

Currently EC policy is stored as in the raw xattr namespace. It would be better to store this in "system" like storage policy.

Raw is meant for attributes which need to be preserved across a distcp, like encryption info. EC policy is more similar to replication factor or storage policy, which can differ between the src and target of a distcp.