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https://issues.apache.org/jira/browse/HDFS-13956?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16640128#comment-16640128
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Hrishikesh Gadre commented on HDFS-13956:
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[~jojochuang] thanks for the review!
{quote}Question: is the goal to identify a file is replicated or erasure-coded?
Or do you intend to identify the ec policy?
If it's for the former, we just need a boolean; if it's for the latter, i'm not
sure the byte number of ec policy means too much outside the NN. IMO, the byte
number is an internal data structure that shouldn't/doesn't mean too much
outside the NN.
{quote}
The goal is to identify if a given file is replicated or erasure coded. I agree
that just exposing a boolean value can work, in fact I had the same thought in
my mind. The advantage of providing the byte value is to keep the iNotify Event
aligned with the FSEditLogOp ( as we are getting the ecPolicyId from the
FSEditLogOp). The disadvantages of this approach are
(a) the client need to decode the byte value correctly (i.e. ecPolicyId == 0
means replicated file vs ecPolicyId > 0 means erasure coded file).
(b) need to wrap ecPolicyId inside an Optional to handle backwards/forward
compatibility.
Exposing a boolean will avoid both these limitations. So I will make that
change.
{quote}On an unrelated note, it looks like we should keep the fields in
FSEditLog.AddCloseOp in sync with CreateEvent. That means CreateEvent should
also have storagePolicyId field as well. (and xAttrs and aclEntries for that
matter)
{quote}
Sure. Would it be OK to handle this as part of a separate jira?
> iNotify should include information to identify a file as either replicated or
> erasure coded
> -------------------------------------------------------------------------------------------
>
> Key: HDFS-13956
> URL: https://issues.apache.org/jira/browse/HDFS-13956
> Project: Hadoop HDFS
> Issue Type: Improvement
> Affects Versions: 3.0.0
> Reporter: Hrishikesh Gadre
> Assignee: Hrishikesh Gadre
> Priority: Minor
> Attachments: HDFS-13956-001.patch, HDFS-13956-002.patch,
> HDFS-13956-003.patch
>
>
> Currently iNotify does not provide information to identify if a given file is
> using replication or erasure coding mode. This would be very useful for the
> downstream applications using iNotify functionality (e.g. to tag/search files
> using erasure coding).
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