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https://issues.apache.org/jira/browse/HDFS-9959?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15202470#comment-15202470
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Tsz Wo Nicholas Sze commented on HDFS-9959:
-------------------------------------------
> ... We don't want to keep more state in the NN than necessary. Also access to
> missingBlocks needs to be synchronized in some way. I am not sure this is
> worth the effort and risk, tbh.
The missing block info seems useful as [~zhaoyunjiong] described. How about
implementing the logging using a ThreadLocal variable? For example, we may add
the following static class to BlocksMap and then call init() and log(..)
outside the lock.
{code}
//BlocksMap
/** For logging missing blocks */
static class MissingBlockLog {
private static final ThreadLocal<List<Block>> missingBlocks4Logging = new
ThreadLocal<>();
static void init() {
missingBlocks4Logging.set(new LinkedList<Block>());
}
static void add(Block b) {
final List<Block> missing = missingBlocks4Logging.get();
if (missing != null) {
missing.add(b);
}
}
static void log(Object name) {
final List<Block> missing = missingBlocks4Logging.get();
missingBlocks4Logging.set(null);
final int size = missing.size();
if (size > 0) {
NameNode.blockStateChangeLog.warn("After removed " + name
+ ", no live nodes contain the following " + size + " blocks: "
+ missing);
}
}
}
{code}
> add log when block removed from last live datanode
> --------------------------------------------------
>
> Key: HDFS-9959
> URL: https://issues.apache.org/jira/browse/HDFS-9959
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode
> Reporter: yunjiong zhao
> Assignee: yunjiong zhao
> Priority: Minor
> Attachments: HDFS-9959.1.patch, HDFS-9959.patch
>
>
> Add logs like "BLOCK* No live nodes contain block blk_1073741825_1001, last
> datanode contain it is node: 127.0.0.1:65341" in BlockStateChange should help
> to identify which datanode should be fixed first to recover missing blocks.
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