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https://issues.apache.org/jira/browse/HDFS-8580?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14586398#comment-14586398
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Jing Zhao commented on HDFS-8580:
---------------------------------
The 002 patch looks good to me. One comment is that while saving an fsimage,
the {{fsn.getErasureCodingZoneForPath(n.getName())}} call is very expensive
since it has to regenerate a full path and resolve it. Thus how about just
retrieving the cell size from the INode's local striped block info?
{code}
+ final int cellSize = fsn.getErasureCodingZoneForPath(n.getName())
+ .getCellSize();
+ builder.setCellSize(cellSize);
{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-8580.00.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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