Manoj Govindassamy created HDFS-11553:
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Summary: Erasure Coding: Missing parity blocks in the block group
are warned as corrupt blocks
Key: HDFS-11553
URL: https://issues.apache.org/jira/browse/HDFS-11553
Project: Hadoop HDFS
Issue Type: Sub-task
Reporter: Manoj Govindassamy
Assignee: Manoj Govindassamy
Currently, {{DFSStripedOutputStream}} verifies if the allocated block locations
are at least numDataBlocks length. That is, for the EC Policy RS-6-3-64K,
though the total needed DNs for a full EC Block Group is 9, Clients will be
able to successfully create a DFSStripedOutputStream with just 6 DNs. Moreover,
the output stream thus created with less DNs will totally ignore writing Parity
Blocks. HDFS-11552 is tracking the improvement needed to accommodate Parity
Blocks along with Data Blocks from the same Block Group.
{code}
[Thread-5] WARN hdfs.DFSOutputStream
(DFSStripedOutputStream.java:allocateNewBlock(497)) - Failed to get block
location for parity block, index=6
[Thread-5] WARN hdfs.DFSOutputStream
(DFSStripedOutputStream.java:allocateNewBlock(497)) - Failed to get block
location for parity block, index=7
[Thread-5] WARN hdfs.DFSOutputStream
(DFSStripedOutputStream.java:allocateNewBlock(497)) - Failed to get block
location for parity block, index=8
{code}
In the above case, upon file stream close we get the following warning message
when the parity blocks are not yet written out. The warning message claims that
there are 3 corrupt blocks, which is in-correct. Its just the EC redundancy is
not sufficient and not corrupt or lost yet. This warning message in the context
of above usecase need to be fixed.
{code}
INFO namenode.FSNamesystem (FSNamesystem.java:checkBlocksComplete(2726)) -
BLOCK* blk_-9223372036854775792_1002 is COMMITTED but not COMPLETE(numNodes= 0
< minimum = 6) in file /ec/test1
INFO hdfs.StateChange (FSNamesystem.java:completeFile(2679)) - DIR*
completeFile: /ec/test1 is closed by DFSClient_NONMAPREDUCE_-1900076771_17
WARN hdfs.DFSOutputStream (DFSStripedOutputStream.java:logCorruptBlocks(1117))
- Block group <1> has 3 corrupt blocks. It's at high risk of losing data.
{code}
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