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https://issues.apache.org/jira/browse/HDFS-9818?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15153241#comment-15153241
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Tsz Wo Nicholas Sze commented on HDFS-9818:
-------------------------------------------
- We may also make chooseSource4SimpleReplication static and slightly shorter.
{code}
private static int chooseSource4SimpleReplication(DatanodeDescriptor[] dds) {
final Map<String, List<Integer>> map = new HashMap<>();
for (int i = 0; i < dds.length; i++) {
final String rack = dds[i].getNetworkLocation();
List<Integer> list = map.get(rack);
if (list == null) {
list = new ArrayList<>();
map.put(rack, list);
}
list.add(i);
}
List<Integer> max = null;
for (Map.Entry<String, List<Integer>> entry : map.entrySet()) {
if (max == null || entry.getValue().size() > max.size()) {
max = entry.getValue();
}
}
return max.get(0);
}
{code}
> Correctly handle EC reconstruction work caused by not enough racks
> ------------------------------------------------------------------
>
> Key: HDFS-9818
> URL: https://issues.apache.org/jira/browse/HDFS-9818
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: datanode, namenode
> Affects Versions: 3.0.0
> Reporter: Takuya Fukudome
> Assignee: Jing Zhao
> Attachments: HDFS-9818.000.patch, HDFS-9818.001.patch
>
>
> This is reported by [~tfukudom]:
> In a system test where 1 of 7 datanode racks were stopped,
> {{HadoopIllegalArgumentException}} was seen on DataNode side while
> reconstructing missing EC blocks:
> {code}
> 2016-02-16 11:09:06,672 WARN datanode.DataNode
> (ErasureCodingWorker.java:run(482)) - Failed to recover striped block:
> BP-480558282-172.29.4.13-1453805190696:blk_-9223372036850962784_278270
> org.apache.hadoop.HadoopIllegalArgumentException: Inputs not fully
> corresponding to erasedIndexes in null places. erasedOrNotToReadIndexes: [1,
> 2, 6], erasedIndexes: [3]
> at
> org.apache.hadoop.io.erasurecode.rawcoder.RSRawDecoder.doDecode(RSRawDecoder.java:166)
> at
> org.apache.hadoop.io.erasurecode.rawcoder.AbstractRawErasureDecoder.decode(AbstractRawErasureDecoder.java:84)
> at
> org.apache.hadoop.io.erasurecode.rawcoder.RSRawDecoder.decode(RSRawDecoder.java:89)
> at
> org.apache.hadoop.hdfs.server.datanode.erasurecode.ErasureCodingWorker$ReconstructAndTransferBlock.recoverTargets(ErasureCodingWorker.java:683)
> at
> org.apache.hadoop.hdfs.server.datanode.erasurecode.ErasureCodingWorker$ReconstructAndTransferBlock.run(ErasureCodingWorker.java:465)
> {code}
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