hdfs-default配置说明等

为方便查询故在此列出

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<!-- Do not modify this file directly.  Instead, copy entries that you -->
<!-- wish to modify from this file into hdfs-site.xml and change them -->
<!-- there.  If hdfs-site.xml does not already exist, create it.      -->

<configuration>

<property>
  <name>dfs.namenode.logging.level</name>
  <value>info</value>
  <description>The logging level for dfs namenode. Other values are "dir"(trac
e namespace mutations), "block"(trace block under/over replications and block
creations/deletions), or "all".</description>
</property>

<property>
  <name>dfs.secondary.http.address</name>
  <value>0.0.0.0:50090</value>
  <description>
    The secondary namenode http server address and port.
    If the port is 0 then the server will start on a free port.
  </description>
</property>

<property>
  <name>dfs.datanode.address</name>
  <value>0.0.0.0:50010</value>
  <description>
    The address where the datanode server will listen to.
    If the port is 0 then the server will start on a free port.
  </description>
</property>

<property>
  <name>dfs.datanode.http.address</name>
  <value>0.0.0.0:50075</value>
  <description>
    The datanode http server address and port.
    If the port is 0 then the server will start on a free port.
  </description>
</property>

<property>
  <name>dfs.datanode.ipc.address</name>
  <value>0.0.0.0:50020</value>
  <description>
    The datanode ipc server address and port.
    If the port is 0 then the server will start on a free port.
  </description>
</property>

<property>
  <name>dfs.datanode.handler.count</name>
  <value>3</value>
  <description>The number of server threads for the datanode.</description>
</property>

<property>
  <name>dfs.http.address</name>
  <value>0.0.0.0:50070</value>
  <description>
    The address and the base port where the dfs namenode web ui will listen on.
    If the port is 0 then the server will start on a free port.
  </description>
</property>

<property>
  <name>dfs.https.enable</name>
  <value>false</value>
  <description>Decide if HTTPS(SSL) is supported on HDFS
  </description>
</property>

<property>
  <name>dfs.https.need.client.auth</name>
  <value>false</value>
  <description>Whether SSL client certificate authentication is required
  </description>
</property>

<property>
  <name>dfs.https.server.keystore.resource</name>
  <value>ssl-server.xml</value>
  <description>Resource file from which ssl server keystore
  information will be extracted
  </description>
</property>

<property>
  <name>dfs.https.client.keystore.resource</name>
  <value>ssl-client.xml</value>
  <description>Resource file from which ssl client keystore
  information will be extracted
  </description>
</property>

<property>
  <name>dfs.datanode.https.address</name>
  <value>0.0.0.0:50475</value>
</property>

<property>
  <name>dfs.https.address</name>
  <value>0.0.0.0:50470</value>
</property>

 <property>
  <name>dfs.datanode.dns.interface</name>
  <value>default</value>
  <description>The name of the Network Interface from which a data node should 
  report its IP address.
  </description>
 </property>
 
<property>
  <name>dfs.datanode.dns.nameserver</name>
  <value>default</value>
  <description>The host name or IP address of the name server (DNS)
  which a DataNode should use to determine the host name used by the
  NameNode for communication and display purposes.
  </description>
 </property>
 
 
 
<property>
  <name>dfs.replication.considerLoad</name>
  <value>true</value>
  <description>Decide if chooseTarget considers the target's load or not
  </description>
</property>
<property>
  <name>dfs.default.chunk.view.size</name>
  <value>32768</value>
  <description>The number of bytes to view for a file on the browser.
  </description>
</property>

<property>
  <name>dfs.datanode.du.reserved</name>
  <value>0</value>
  <description>Reserved space in bytes per volume. Always leave this much space free for non dfs use.
  </description>
</property>

<property>
  <name>dfs.name.dir</name>
  <value>${hadoop.tmp.dir}/dfs/name</value>
  <description>Determines where on the local filesystem the DFS name node
      should store the name table(fsimage).  If this is a comma-delimited list
      of directories then the name table is replicated in all of the
      directories, for redundancy. </description>
</property>

<property>
  <name>dfs.name.edits.dir</name>
  <value>${dfs.name.dir}</value>
  <description>Determines where on the local filesystem the DFS name node
      should store the transaction (edits) file. If this is a comma-delimited list
      of directories then the transaction file is replicated in all of the 
      directories, for redundancy. Default value is same as dfs.name.dir
  </description>
</property>
<property>
  <name>dfs.web.ugi</name>
  <value>webuser,webgroup</value>
  <description>The user account used by the web interface.
    Syntax: USERNAME,GROUP1,GROUP2, ...
  </description>
</property>

<property>
  <name>dfs.permissions</name>
  <value>true</value>
  <description>
    If "true", enable permission checking in HDFS.
    If "false", permission checking is turned off,
    but all other behavior is unchanged.
    Switching from one parameter value to the other does not change the mode,
    owner or group of files or directories.
  </description>
</property>

<property>
  <name>dfs.permissions.supergroup</name>
  <value>supergroup</value>
  <description>The name of the group of super-users.</description>
</property>

<property>
  <name>dfs.data.dir</name>
  <value>${hadoop.tmp.dir}/dfs/data</value>
  <description>Determines where on the local filesystem an DFS data node
  should store its blocks.  If this is a comma-delimited
  list of directories, then data will be stored in all named
  directories, typically on different devices.
  Directories that do not exist are ignored.
  </description>
</property>

<property>
  <name>dfs.replication</name>
  <value>3</value>
  <description>Default block replication. 
  The actual number of replications can be specified when the file is created.
  The default is used if replication is not specified in create time.
  </description>
</property>

<property>
  <name>dfs.replication.max</name>
  <value>512</value>
  <description>Maximal block replication. 
  </description>
</property>

<property>
  <name>dfs.replication.min</name>
  <value>1</value>
  <description>Minimal block replication. 
  </description>
</property>

<property>
  <name>dfs.block.size</name>
  <value>67108864</value>
  <description>The default block size for new files.</description>
</property>

<property>
  <name>dfs.df.interval</name>
  <value>60000</value>
  <description>Disk usage statistics refresh interval in msec.</description>
</property>

<property>
  <name>dfs.client.block.write.retries</name>
  <value>3</value>
  <description>The number of retries for writing blocks to the data nodes, 
  before we signal failure to the application.
  </description>
</property>

<property>
  <name>dfs.blockreport.intervalMsec</name>
  <value>3600000</value>
  <description>Determines block reporting interval in milliseconds.</description>
</property>

<property>
  <name>dfs.blockreport.initialDelay</name>  <value>0</value>
  <description>Delay for first block report in seconds.</description>
</property>

<property>
  <name>dfs.heartbeat.interval</name>
  <value>3</value>
  <description>Determines datanode heartbeat interval in seconds.</description>
</property>

<property>
  <name>dfs.namenode.handler.count</name>
  <value>10</value>
  <description>The number of server threads for the namenode.</description>
</property>

<property>
  <name>dfs.safemode.threshold.pct</name>
  <value>0.999f</value>
  <description>
    Specifies the percentage of blocks that should satisfy 
    the minimal replication requirement defined by dfs.replication.min.
    Values less than or equal to 0 mean not to start in safe mode.
    Values greater than 1 will make safe mode permanent.
  </description>
</property>

<property>
  <name>dfs.safemode.extension</name>
  <value>30000</value>
  <description>
    Determines extension of safe mode in milliseconds 
    after the threshold level is reached.
  </description>
</property>

<property>
  <name>dfs.balance.bandwidthPerSec</name>
  <value>1048576</value>
  <description>
        Specifies the maximum amount of bandwidth that each datanode
        can utilize for the balancing purpose in term of
        the number of bytes per second.
  </description>
</property>

<property>
  <name>dfs.hosts</name>
  <value></value>
  <description>Names a file that contains a list of hosts that are
  permitted to connect to the namenode. The full pathname of the file
  must be specified.  If the value is empty, all hosts are
  permitted.</description>
</property>

<property>
  <name>dfs.hosts.exclude</name>
  <value></value>
  <description>Names a file that contains a list of hosts that are
  not permitted to connect to the namenode.  The full pathname of the
  file must be specified.  If the value is empty, no hosts are
  excluded.</description>
</property> 

<property>
  <name>dfs.max.objects</name>
  <value>0</value>
  <description>The maximum number of files, directories and blocks
  dfs supports. A value of zero indicates no limit to the number
  of objects that dfs supports.
  </description>
</property>

<property>
  <name>dfs.namenode.decommission.interval</name>
  <value>30</value>
  <description>Namenode periodicity in seconds to check if decommission is 
  complete.</description>
</property>

<property>
  <name>dfs.namenode.decommission.nodes.per.interval</name>
  <value>5</value>
  <description>The number of nodes namenode checks if decommission is complete
  in each dfs.namenode.decommission.interval.</description>
</property>

<property>
  <name>dfs.replication.interval</name>
  <value>3</value>
  <description>The periodicity in seconds with which the namenode computes 
  repliaction work for datanodes. </description>
</property>

<property>
  <name>dfs.access.time.precision</name>
  <value>3600000</value>
  <description>The access time for HDFS file is precise upto this value. 
               The default value is 1 hour. Setting a value of 0 disables
               access times for HDFS.
  </description>
</property>

<property>
  <name>dfs.support.append</name>
  <value>false</value>
  <description>Does HDFS allow appends to files?
               This is currently set to false because there are bugs in the
               "append code" and is not supported in any prodction cluster.
  </description>
</property>

</configuration>