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Lisheng Sun commented on HDFS-14896: ------------------------------------ hi [~ayushtkn] [~sodonnell] Thanks you for paying attention to this patch. {code:java} As we only allocate a single block at a time, why do we need to make this configurable and hence reserve X blocks of space on a datanode?Can you tell us some more about what problem this patch is solving?{code} when dn disk left is a lot little and When the block is allocated by NN, the space left by dn is larger than one block. but the block on dn may not report to nn. in fact,he space left of NN is less than one block. when client write dn, it failed. error info as follow: {code:java} 2019-10-26,08:00:06,286 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: opWriteBlock BP-1433996662-10.114.24.46-1527834893133:blk_1143416676_69848202 received exception org.apache.hadoop.util.DiskChecker$DiskOutOfSpaceException: Out of space: The volume with the most available space (=16781312 B) is less than the block size (=134217728 B). 2019-10-26,08:00:06,287 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: c3-hadoop-srv-st940.bj:13402:DataXceiver error processing WRITE_BLOCK operation src: /10.136.164.23:37753 dst: /10.136.164.47:13402 org.apache.hadoop.util.DiskChecker$DiskOutOfSpaceException: Out of space: The volume with the most available space (=16781312 B) is less than the block size (=134217728 B). {code} so i think it is necessary to make MIN_BLOCKS_FOR_WRITE configurable and we can make it more than 1. Please correct me if i was wrong. Thank you a lot [~ayushtkn] [~sodonnell] > Make MIN_BLOCKS_FOR_WRITE configurable > -------------------------------------- > > Key: HDFS-14896 > URL: https://issues.apache.org/jira/browse/HDFS-14896 > Project: Hadoop HDFS > Issue Type: Improvement > Reporter: Lisheng Sun > Assignee: Lisheng Sun > Priority: Minor > Attachments: HDFS-14896.001.patch, HDFS-14896.002.patch, > HDFS-14896.003(2).patch, HDFS-14896.003.patch, HDFS-14896.004.patch, > HDFS-14896.005.patch > > -- 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