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https://issues.apache.org/jira/browse/FLINK-9061?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16589342#comment-16589342
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ASF GitHub Bot commented on FLINK-9061:
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StephanEwen opened a new pull request #6604: [FLINK-9061] Optionally add
entropy to checkpoint paths better S3 scalability
URL: https://github.com/apache/flink/pull/6604
## What is the purpose of the change
This pull request adds hooks to optionally inject entropy to the checkpoint
path based upon a user defined pattern in the configuration for better S3
scalability.
This is a revised version of #6302 by @indrc (based on Flink 1.4) that ports
the changes to the new FileStateStorage code introduced in Flink 1.5.
## Brief change log
- Adds an optional `CheckpointPathFilter` that is applied to data and
metadata paths before creating the files
- Adds an implementation of that filter that replaces entropy keys with
entropy (data files) or removes the entropy key (metadata files)
- Adds functionality to read the entropy pattern from the config or set it
on the state backend, and configure the CheckpointPathFilter based on that
## Verifying this change
- Added unit tests under `org.apache.flink.runtime.state.filesystem`
## Does this pull request potentially affect one of the following parts:
- Dependencies (does it add or upgrade a dependency): **no**
- The public API, i.e., is any changed class annotated with
`@Public(Evolving)`: **no**
- The serializers: **no**
- The runtime per-record code paths (performance sensitive): **no**
- Anything that affects deployment or recovery: JobManager (and its
components), Checkpointing, Yarn/Mesos, ZooKeeper: **yes**
- The S3 file system connector: **no**
## Documentation
- Does this pull request introduce a new feature? **yes**
- If yes, how is the feature documented? **docs**
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> add entropy to s3 path for better scalability
> ---------------------------------------------
>
> Key: FLINK-9061
> URL: https://issues.apache.org/jira/browse/FLINK-9061
> Project: Flink
> Issue Type: Bug
> Components: FileSystem, State Backends, Checkpointing
> Affects Versions: 1.5.0, 1.4.2
> Reporter: Jamie Grier
> Assignee: Indrajit Roychoudhury
> Priority: Critical
> Labels: pull-request-available
>
> I think we need to modify the way we write checkpoints to S3 for high-scale
> jobs (those with many total tasks). The issue is that we are writing all the
> checkpoint data under a common key prefix. This is the worst case scenario
> for S3 performance since the key is used as a partition key.
>
> In the worst case checkpoints fail with a 500 status code coming back from S3
> and an internal error type of TooBusyException.
>
> One possible solution would be to add a hook in the Flink filesystem code
> that allows me to "rewrite" paths. For example say I have the checkpoint
> directory set to:
>
> s3://bucket/flink/checkpoints
>
> I would hook that and rewrite that path to:
>
> s3://bucket/[HASH]/flink/checkpoints, where HASH is the hash of the original
> path
>
> This would distribute the checkpoint write load around the S3 cluster evenly.
>
> For reference:
> https://aws.amazon.com/premiumsupport/knowledge-center/s3-bucket-performance-improve/
>
> Any other people hit this issue? Any other ideas for solutions? This is a
> pretty serious problem for people trying to checkpoint to S3.
>
> -Jamie
>
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