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https://issues.apache.org/jira/browse/HDFS-9837?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15159001#comment-15159001
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Rakesh R commented on HDFS-9837:
--------------------------------
Thanks [~jingzhao] for the work. {{EnumCounters<StoredReplicaState>}} idea
looks pretty good. I've few comments about the changes, please take a look at
it.
# Should be StoredReplicaState.DECOMMISSIONED, isn't it?
{code}
} else if (node.isDecommissioned()) {
- decommissioned++;
+ counters.add(StoredReplicaState.DECOMMISSIONING, 1);
{code}
# I could see BlockInfoStriped#findSlot() is expanding the capacity beyond
{{#getTotalBlockNum}}. I think while counting the replicas it is checking only
upto totalBlock, so it will miss few replica checks.
{code}
BlockManager.java
+ private void countReplicasForStripedBlock(
+ EnumCounters<StoredReplicaState> counters, BlockInfoStriped block,
+ Collection<DatanodeDescriptor> nodesCorrupt, boolean inStartupSafeMode) {
+ BitSet bitSet = new BitSet(block.getTotalBlockNum());
{code}
{code}
BlockInfoStriped.java
private int findSlot() {
int i = getTotalBlockNum();
for (; i < getCapacity(); i++) {
if (getStorageInfo(i) == null) {
return i;
}
}
// need to expand the storage size
ensureCapacity(i + 1, true);
return i;
}
{code}
# I'd prefer using {{#getCapacity()}} instead of {{storages.length}}. Also, use
{{#getStorageInfo(index)}} instead of
{code}
storages[index] and storages[i]
{code}
> BlockManager#countNodes should be able to detect duplicated internal blocks
> ---------------------------------------------------------------------------
>
> Key: HDFS-9837
> URL: https://issues.apache.org/jira/browse/HDFS-9837
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Affects Versions: 3.0.0
> Reporter: Jing Zhao
> Assignee: Jing Zhao
> Attachments: HDFS-9837.000.patch, HDFS-9837.001.patch,
> HDFS-9837.002.patch
>
>
> Currently {{BlockManager#countNodes}} only counts the number of
> replicas/internal blocks thus it cannot detect the under-replicated scenario
> where a striped EC block has 9 internal blocks but contains duplicated
> data/parity blocks. E.g., b8 is missing while 2 b0 exist:
> b0, b1, b2, b3, b4, b5, b6, b7, b0
> If the NameNode keeps running, NN is able to detect the duplication of b0 and
> will put the block into the excess map. {{countNodes}} excludes internal
> blocks captured in the excess map thus can return the correct number of live
> replicas. However, if NN restarts before sending out the reconstruction
> command, the missing internal block cannot be detected anymore. The following
> steps can reproduce the issue:
> # create an EC file
> # kill DN1 and wait for the reconstruction to happen
> # start DN1 again
> # kill DN2 and restart NN immediately
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