Zhe Zhang created HDFS-7652:
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Summary: Process block reports for erasure coded blocks
Key: HDFS-7652
URL: https://issues.apache.org/jira/browse/HDFS-7652
Project: Hadoop HDFS
Issue Type: Sub-task
Reporter: Zhe Zhang
Assignee: Zhe Zhang
HDFS-7339 adds support in NameNode for persisting block groups. For memory
efficiency, erasure coded blocks under the striping layout are not stored in
{{BlockManager#blocksMap}}. Instead, entire block groups are stored in
{{BlockGroupManager#blockGroups}}. When a block report arrives from the
DataNode, it should be processed under the block group that it belongs to. The
following naming protocol is used to calculate the group of a given block:
{code}
* HDFS-EC introduces a hierarchical protocol to name blocks and groups:
* Contiguous: {reserved block IDs | flag | block ID}
* Striped: {reserved block IDs | flag | block group ID | index in group}
*
* Following n bits of reserved block IDs, The (n+1)th bit in an ID
* distinguishes contiguous (0) and striped (1) blocks. For a striped block,
* bits (n+2) to (64-m) represent the ID of its block group, while the last m
* bits represent its index of the group. The value m is determined by the
* maximum number of blocks in a group (MAX_BLOCKS_IN_GROUP).
{code}
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