[HDFS-4078] Handle replication in snapshots

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: Snapshot (HDFS-2802)
• Component/s: namenode
• Labels: needs-test
• Hadoop Flags: Reviewed
• Assignee: Tsz-wo Sze
• Reporter: Tsz-wo Sze
• Created: 19/Oct/12 00:35
• Updated: 22/Oct/12 18:51
• Resolved: 22/Oct/12 00:13

Description

Without snapshots, file replication is the same as block replication.

With snapshot, the file replication R_o of the original file and the file replication R_s of the snapshot file could possibly be different. Since the blocks are shared between the original file and the snapshot file, block replication is max(R_o, R_s). If there are more than one snapshots, block replication is the max file replication of the original file and all snapshot files.