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https://issues.apache.org/jira/browse/HDFS-7859?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15857239#comment-15857239
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Andrew Wang commented on HDFS-7859:
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Thanks for the comments Zhe, inline,
bq. Other than "ID/name that we already use, or an ID/name we might want to
hardcode later", what other validations do you have in mind?
I think it's problematic if user-defined policies are in the same
id-space/namespace as system-defined policies. Separating these spaces would
eliminate the possibility of overlap and the need for validation.
bq. If we do decide to add pluggable EC policies in 3.0 GA, can we add an
on-off config option for the entire pluggable logic and default to off?
Yea, I think that works. IMO it's unlikely we get to pluggable policies at all
in 3.0. The goal as I understand it was to support something like LRC as a
pluggable policy, but that requires hooking into blockplacement and recovery.
We haven't 100% finished those yet even for our built-in policies, and making
these interfaces pluggable will be tough.
So, I'd like to co-opt this JIRA to add APIs for defining allowed policies as
well as the default policy for a cluster. We'll need new shell commands for
doing this too.
[~xinwei] / [~surendrasingh] are you interested in working on this? If not, I
can pick it up.
> Erasure Coding: Persist erasure coding policies in NameNode
> -----------------------------------------------------------
>
> Key: HDFS-7859
> URL: https://issues.apache.org/jira/browse/HDFS-7859
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Kai Zheng
> Assignee: Xinwei Qin
> Priority: Blocker
> Labels: BB2015-05-TBR, hdfs-ec-3.0-must-do
> Attachments: HDFS-7859.001.patch, HDFS-7859.002.patch,
> HDFS-7859.004.patch, HDFS-7859.005.patch, HDFS-7859.006.patch,
> HDFS-7859.007.patch, HDFS-7859.008.patch, HDFS-7859.009.patch,
> HDFS-7859-HDFS-7285.002.patch, HDFS-7859-HDFS-7285.002.patch,
> HDFS-7859-HDFS-7285.003.patch
>
>
> In meetup discussion with [~zhz] and [~jingzhao], it's suggested that we
> persist EC schemas in NameNode centrally and reliably, so that EC zones can
> reference them by name efficiently.
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