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https://issues.apache.org/jira/browse/HDFS-8580?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14588530#comment-14588530
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Jing Zhao commented on HDFS-8580:
---------------------------------
# Let's use "optional" here to avoid incompatibility when we change the
protobuf definition again.
{code}
message StripedBlocksFeature {
// store striped blocks related information
+ required uint32 cellSize = 1;
}
{code}
# If the file does not have any block, we do not need to load its blocks. And
in this case we actually do not need to write this info into fsimage. This is
another reason we should define cellSize field as optional.
{code}
+ } else {
+ cellSize =
fsn.getErasureCodingZoneForPath(n.getName()).getCellSize();
}
{code}
> Erasure coding: Persist cellSize in BlockInfoStriped and StripedBlocksFeature
> -----------------------------------------------------------------------------
>
> Key: HDFS-8580
> URL: https://issues.apache.org/jira/browse/HDFS-8580
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Walter Su
> Assignee: Walter Su
> Attachments: HDFS-8580-HDFS-7285.01.patch,
> HDFS-8580-HDFS-7285.02.patch, HDFS-8580-HDFS-7285.03.patch, HDFS-8580.00.patch
>
>
> Zhe Zhang, Kai Zheng and I had a offline discussion. Here is what we thought:
> Add a cellSize field in BlockInfoStriped as a workaround, and deal with
> memory usage in follow-on.(HDFS-8059)
> discussion in HDFS-8494:
> from Walter Su:
> {quote}
> I think BlockInfoStriped needs to keep cellSize.
> {quote}
> from [~vinayrpet]:
> {quote}
> I too was thinking the same when the FSImageLoader problem has came up. This
> will increase the memory usage by ~4bytes for each block though.
> {quote}
> from [~jingzhao]
> {quote}
> -Also, we should consider adding a chunk size field to StripedBlockProto and
> removing the cell size field from HdfsFileStatus. In this way we can access
> the chunk size information in the storage layer.-
> {quote}
> ==
> update:
> from [~jingzhao]
> {quote}
> For fsimage part, since HDFS-8585 just removes StripedBlockProto, I guess
> what we can do here is to either 1) add the cellSize information into
> StripedBlocksFeature in fsimage.proto, or 2) bring StripedBlockProto back and
> put block info and cell size there.
> {quote}
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