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https://issues.apache.org/jira/browse/HDFS-12682?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Xiao Chen updated HDFS-12682:
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Attachment: HDFS-12682.01.patch
Uploading patch 1 to show the idea. It's not easy to split the metadata part to
HDFS-12686, because the protobuf definition is changed.
Some considerations in this patch:
- Modifying protobuf definition and Public class {{ErasureCodingPolicy}} are
not compatible. But this is fixing the previous bug, so I think the right thing
to do here.
- For the get {{ErasureCodingPolicy}} methods, I went without state for all.
File attributes only care about policy, not its state; file system level (e.g.
{{hdfs ec -getPolicy -path <path>}}) I think since we always require -path,
it's also focusing on the policy rather than its state. If there is requirement
to get the state of a policy without using {{-listPolices}} in the future, we
could add new APIs for that.
Will check tests and think about coverage. Appreciate early reviews / feedback
on the patch.
> ECAdmin -listPolicies will always show policy state as DISABLED
> ---------------------------------------------------------------
>
> Key: HDFS-12682
> URL: https://issues.apache.org/jira/browse/HDFS-12682
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: erasure-coding
> Reporter: Xiao Chen
> Assignee: Xiao Chen
> Labels: hdfs-ec-3.0-must-do
> Attachments: HDFS-12682.01.patch
>
>
> On a real cluster, {{hdfs ec -listPolicies}} will always show policy state as
> DISABLED.
> {noformat}
> [hdfs@nightly6x-1 root]$ hdfs ec -listPolicies
> Erasure Coding Policies:
> ErasureCodingPolicy=[Name=RS-10-4-1024k, Schema=[ECSchema=[Codec=rs,
> numDataUnits=10, numParityUnits=4]], CellSize=1048576, Id=5, State=DISABLED]
> ErasureCodingPolicy=[Name=RS-3-2-1024k, Schema=[ECSchema=[Codec=rs,
> numDataUnits=3, numParityUnits=2]], CellSize=1048576, Id=2, State=DISABLED]
> ErasureCodingPolicy=[Name=RS-6-3-1024k, Schema=[ECSchema=[Codec=rs,
> numDataUnits=6, numParityUnits=3]], CellSize=1048576, Id=1, State=DISABLED]
> ErasureCodingPolicy=[Name=RS-LEGACY-6-3-1024k,
> Schema=[ECSchema=[Codec=rs-legacy, numDataUnits=6, numParityUnits=3]],
> CellSize=1048576, Id=3, State=DISABLED]
> ErasureCodingPolicy=[Name=XOR-2-1-1024k, Schema=[ECSchema=[Codec=xor,
> numDataUnits=2, numParityUnits=1]], CellSize=1048576, Id=4, State=DISABLED]
> [hdfs@nightly6x-1 root]$ hdfs ec -getPolicy -path /ecec
> XOR-2-1-1024k
> {noformat}
> This is because when [deserializing
> protobuf|https://github.com/apache/hadoop/blob/branch-3.0.0-beta1/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelperClient.java#L2942],
> the static instance of [SystemErasureCodingPolicies
> class|https://github.com/apache/hadoop/blob/branch-3.0.0-beta1/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/SystemErasureCodingPolicies.java#L101]
> is first checked, and always returns the cached policy objects, which are
> created by default with state=DISABLED.
> All the existing unit tests pass, because that static instance that the
> client (e.g. ECAdmin) reads in unit test is updated by NN. :)
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