Bryan Beaudreault created HDFS-16261:
----------------------------------------

             Summary: Configurable grace period around deletion of invalidated 
blocks
                 Key: HDFS-16261
                 URL: https://issues.apache.org/jira/browse/HDFS-16261
             Project: Hadoop HDFS
          Issue Type: New Feature
            Reporter: Bryan Beaudreault
            Assignee: Bryan Beaudreault


When a block is moved with REPLACE_BLOCK, the new location is recorded in the 
NameNode and the NameNode instructs the old host to in invalidate the block 
using DNA_INVALIDATE. As it stands today, this invalidation is async but tends 
to happen relatively quickly.

I'm working on a feature for HBase which enables efficient healing of locality 
through Balancer-style low level block moves. One issue is that HBase tends to 
keep open long running DFSInputStreams and moving blocks from under them causes 
lots of warns in the RegionServer and increases long tail latencies due to the 
necessary retries in the DFSClient.

One way I'd like to fix this is to provide a configurable grace period on async 
invalidations. This would give the DFSClient enough time to refresh block 
locations before hitting any errors.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)

---------------------------------------------------------------------
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