hadoop-error:DiskChecker$DiskErrorException: Invalid volume failure config value

2012-12-17 10:58:59,925 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: org.apache.hadoop.util.DiskChecker$DiskErrorException: Invalid
volume failure  config value: 3
        at org.apache.hadoop.hdfs.server.datanode.FSDataset.(FSDataset.java:1025)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.startDataNode(DataNode.java:414)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.(DataNode.java:305)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.makeInstance(DataNode.java:1606)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.instantiateDataNode(DataNode.java:1546)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.createDataNode(DataNode.java:1564)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.secureMain(DataNode.java:1690)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:1707)

 

新建了几台机器的集群，启动datanode时候报了这个错。

主要原因是因为dfs.datanode.failed.volumes.tolerated 参数配置了3，

这个参数的含义：The number of volumes that are allowed to fail before a datanode stops offering service. By default any volume failure will cause a datanode to shutdown.

 

datanode允许磁盘损坏的个数 ，datanode在启动时候会使用dfs.data.dir下配置的文件夹（用于存储block的），若是有一些不可以用且个数>上面配置的那个 值，这启动失败，代码见：org.apache.hadoop.hdfs.server.datanode.FSDataset

 

public FSDataset(DataStorage storage, Configuration conf) throws IOException {
    this.maxBlocksPerDir = conf.getInt("dfs.datanode.numblocks", 64);
    
    // The number of volumes required for operation is the total number 
    // of volumes minus the number of failed volumes we can tolerate.
    final int volFailuresTolerated =
      conf.getInt("dfs.datanode.failed.volumes.tolerated", 0);
    String[] dataDirs = conf.getTrimmedStrings(DataNode.DATA_DIR_KEY);
    int volsConfigured = (dataDirs == null) ? 0 : dataDirs.length;
    int volsFailed = volsConfigured - storage.getNumStorageDirs();
    validVolsRequired = volsConfigured - volFailuresTolerated;

    if (volFailuresTolerated < 0 || volFailuresTolerated >= volsConfigured) {
      throw new DiskErrorException("Invalid volume failure "
          + " config value: " + volFailuresTolerated);
    }

 

由于dfs.data.dir只配了一个目录，所以将 dfs.datanode.failed.volumes.tolerated设置为0后，问题解决。