[HADOOP-2065] Replication policy for corrupted block

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.14.1
• Fix Version/s: 0.18.0
• Hadoop Flags: Incompatible change
• Release Note: Added "corrupt" flag to LocatedBlock to indicate that all replicas of the block thought to be corrupt.
• Assignee: Lohit Vijaya Renu
• Reporter: Koji Noguchi
• Created: 16/Oct/07 19:09
• Updated: 08/Jul/09 16:42
• Resolved: 12/May/08 21:54

Description

Thanks to HADOOP-1955, even if one of the replica is corrupted, the block should get replicated from a good replica relatively fast.

Created this ticket to continue the discussion from http://issues.apache.org/jira/browse/HADOOP-1955#action_12531162.

2. Delete corrupted source replica

3. If all replicas are corrupt, stop replication.

For (2), it'll be nice if the namenode can delete the corrupted block if there's a good replica on other nodes.

For (3), I prefer if the namenode can still replicate the block.
Before 0.14, if the file was corrupted, users were still able to pull the data and decide if they want to delete those files. (HADOOP-2063)
In 0.14 and later, we cannot/don't replicate these blocks so they eventually get lost.

To make the matters worse, if the corrupted file is accessed, all the corrupted replicas would be deleted except for one and stay as replication factor of 1 forever.

Issue Links

• relates to: HADOOP-1955 Corrupted block replication retries for ever
• relates to: HADOOP-4351 ArrayIndexOutOfBoundsException during fsck