Ravi Prakash reassigned HDFS-8344:

    Assignee:     (was: Ravi Prakash)

> NameNode doesn't recover lease for files with missing blocks
> ------------------------------------------------------------
>                 Key: HDFS-8344
>                 URL: https://issues.apache.org/jira/browse/HDFS-8344
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: namenode
>    Affects Versions: 2.7.0
>            Reporter: Ravi Prakash
>            Priority: Major
>         Attachments: HDFS-8344.01.patch, HDFS-8344.02.patch, 
> HDFS-8344.03.patch, HDFS-8344.04.patch, HDFS-8344.05.patch, 
> HDFS-8344.06.patch, HDFS-8344.07.patch, HDFS-8344.08.patch, 
> HDFS-8344.09.patch, HDFS-8344.10.patch, TestHadoop.java
> I found another\(?) instance in which the lease is not recovered. This is 
> reproducible easily on a pseudo-distributed single node cluster
> # Before you start it helps if you set. This is not necessary, but simply 
> reduces how long you have to wait
> {code}
>       public static final long LEASE_SOFTLIMIT_PERIOD = 30 * 1000;
>       public static final long LEASE_HARDLIMIT_PERIOD = 2 * 
> {code}
> # Client starts to write a file. (could be less than 1 block, but it hflushed 
> so some of the data has landed on the datanodes) (I'm copying the client code 
> I am using. I generate a jar and run it using $ hadoop jar TestHadoop.jar)
> # Client crashes. (I simulate this by kill -9 the $(hadoop jar 
> TestHadoop.jar) process after it has printed "Wrote to the bufferedWriter"
> # Shoot the datanode. (Since I ran on a pseudo-distributed cluster, there was 
> only 1)
> I believe the lease should be recovered and the block should be marked 
> missing. However this is not happening. The lease is never recovered.
> The effect of this bug for us was that nodes could not be decommissioned 
> cleanly. Although we knew that the client had crashed, the Namenode never 
> released the leases (even after restarting the Namenode) (even months 
> afterwards). There are actually several other cases too where we don't 
> consider what happens if ALL the datanodes die while the file is being 
> written, but I am going to punt on that for another time.

This message was sent by Atlassian JIRA

To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org

Reply via email to