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https://issues.apache.org/jira/browse/HDFS-10759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15556534#comment-15556534
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Jing Zhao commented on HDFS-10759:
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Yeah I also think the idea is good. But we need to guarantee the compatibility:
the old fsimage should still be supported and new enum types should be easily
added (which means we may need to add UNKNOWN_TYPE in the enum according to the
link).
> Change fsimage bool isStriped from boolean to an enum
> -----------------------------------------------------
>
> Key: HDFS-10759
> URL: https://issues.apache.org/jira/browse/HDFS-10759
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs
> Affects Versions: 3.0.0-alpha1, 3.0.0-beta1, 3.0.0-alpha2
> Reporter: Ewan Higgs
> Labels: hdfs-ec-3.0-must-do
> Attachments: HDFS-10759.0001.patch
>
>
> The new erasure coding project has updated the protocol for fsimage such that
> the {{INodeFile}} has a boolean '{{isStriped}}'. I think this is better as an
> enum or integer since a boolean precludes any future block types.
> For example:
> {code}
> enum BlockType {
> CONTIGUOUS = 0,
> STRIPED = 1,
> }
> {code}
> We can also make this more robust to future changes where there are different
> block types supported in a staged rollout. Here, we would use
> {{UNKNOWN_BLOCK_TYPE}} as the first value since this is the default value.
> See
> [here|http://androiddevblog.com/protocol-buffers-pitfall-adding-enum-values/]
> for more discussion.
> {code}
> enum BlockType {
> UNKNOWN_BLOCK_TYPE = 0,
> CONTIGUOUS = 1,
> STRIPED = 2,
> }
> {code}
> But I'm not convinced this is necessary since there are other enums that
> don't use this approach.
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