Li Cheng created HDDS-2010:
------------------------------
Summary: PipelineID management for multi-raft, in SCM or in
datanode?
Key: HDDS-2010
URL: https://issues.apache.org/jira/browse/HDDS-2010
Project: Hadoop Distributed Data Store
Issue Type: Improvement
Components: Ozone Datanode
Reporter: Li Cheng
Assignee: Li Cheng
With the intention to support
[multi-raft|https://issues.apache.org/jira/browse/HDDS-1564], I wanna bring up
a question on how the pipeline unique ids be managed. Since every datanode can
be member in multiple raft pipelines, the pipeline ids need to be persisted
with the datanode for recovery purpose (we can talk about recovery later).
Generally there are two options:
# Store in datanode (like datanodeDetails) and every time pipelines mapping
change on single datanode, pipeline ids will be serialized to local file. This
way will lead to many more local serialization of things like datanodeDetails,
but the updates are only for local datanode change. Improvement can be made
like linking a serializable object to datanodeDetails and datanode keeps
updating the new pipeline ids to the serializable object instead the details
file. On the other hand, since the pipeline ids are stored only in datanode
locally, there will be no global view in SCM. (or we can store a lazy copy?)
* 2. Stored in SCM. SCM can maintain a large mapping between datanode ids and
pipeline ids. But this way will lead to an exponentially increasing frequency
in SCM updates since the pipeline mapping changes are way more complex and
happen all the time. Obviously this gives SCM too much pressure, but it can
also give SCM a global view on the management over datanodes and multi raft
pipelines.
Thoughts? [~xyao] [~Sammi]
--
This message was sent by Atlassian Jira
(v8.3.2#803003)
---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org
