[HDFS-1779] After NameNode restart , Clients can not read partial files even after client invokes Sync.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.20-append
• Fix Version/s: 0.20-append, 0.20.205.0
• Component/s: datanode, namenode

Environment

Linux

• Hadoop Flags: Reviewed
• Assignee: Uma Maheswara Rao G
• Reporter: Uma Maheswara Rao G
• Created: 23/Mar/11 14:42
• Updated: 19/Oct/11 17:38
• Resolved: 14/Sep/11 21:52

Description

In Append HDFS-200 issue,
If file has 10 blocks and after writing 5 blocks if client invokes sync method then NN will persist the blocks information in edits.
After this if we restart the NN, All the DataNodes will reregister with NN. But DataNodes are not sending the blocks being written information to NN. DNs are sending the blocksBeingWritten information in DN startup. So, here NameNode can not find that the 5 persisted blocks belongs to which datanodes. This information can build based on block reports from DN. Otherwise we will loose this 5 blocks information even NN persisted that block information in edits.

Issue Links

• is part of: HDFS-200 In HDFS, sync() not yet guarantees data available to the new readers
• relates to: HDFS-1197 Blocks are considered "complete" prematurely after commitBlockSynchronization or DN restart