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https://issues.apache.org/jira/browse/HBASE-1084?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12746305#action_12746305
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stack commented on HBASE-1084:
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Could it be small cluster issue where timeout for hdfs is ten minutes by
default meantime the NN keeps assigning the dead datanode as home for any new
blocks allocated?
We need to make recommendation for datanode lease lengths -- ones that better
align with our other hbase timings.
> Reinitializable DFS client
> --------------------------
>
> Key: HBASE-1084
> URL: https://issues.apache.org/jira/browse/HBASE-1084
> Project: Hadoop HBase
> Issue Type: Improvement
> Components: io, master, regionserver
> Reporter: Andrew Purtell
>
> HBase is the only long lived DFS client. Tasks handle DFS errors by dying.
> HBase daemons do not and instead depend on dfsclient error recovery
> capability, but that is not sufficiently developed or tested. Several issues
> are a result:
> * HBASE-846: hbase looses its mind when hdfs fills
> * HBASE-879: When dfs restarts or moves blocks around, hbase regionservers
> don't notice
> * HBASE-932: Regionserver restart
> * HBASE-1078: "java.io.IOException: Could not obtain block": allthough file
> is there and accessible through the dfs client
> * hlog indefinitely hung on getting new blocks from dfs on apurtell cluster
> * regions closed due to transient DFS problems during loaded cluster restart
> These issues might also be related:
> * HBASE-15: Could not complete hdfs write out to flush file forcing
> regionserver restart
> * HBASE-667: Hung regionserver; hung on hdfs: writeChunk,
> DFSClient.java:2126, DataStreamer socketWrite
> HBase should reinitialize the fs a few times upon catching fs exceptions,
> with backoff, to compensate. This can be done by making a wrapper around all
> fs operations that releases references to the old fs instance and makes and
> initializes a new instance to retry. All fs users would need to be fixed up
> to handle loss of state around fs wrapper invocations: hlog, memcache
> flusher, hstore, etc.
> Cases of clear unrecoverable failure (are there any?) should be excepted.
> Once the fs wrapper is in place, error recovery scenarios can be tested by
> forcing reinitialization of the fs during PE or other test cases.
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