easyhadoop heapsize 113.81

hadoop:1.2.1 ,easyhadoop:1.2.1 , centos:6.4 。

在使用easyhadoop的时候按照http://blog.csdn.net/fansy1990/article/details/12839441这篇文章的配置会出现集群的heapsize是113.81MB的情况，而且修改hadoop-env.sh中的export HADOOP_HEAPSIZE=1000没有作用。在50070界面看到的cluster summary如下所示：

2651 files and directories, 1117 blocks = 3768 total. Heap Size is 72.88 MB / 113.81 MB (64%) 

使用 hadoop heapsize 113.81作为关键字google，可以看到这样的一篇文章http://grokbase.com/t/cloudera/cdh-user/1358wy4708/heapsize-of-namenode-and-mapreduce，这篇文章也是这个问题。上面分析了多种配置情况，最后算是解决了这个问题。

其实，在easyhadoop配置的时候，需要配置hadoop-env.sh文件，笔者当时是从一个地方拷贝的hadoop-evn.sh文件然后直接粘贴的。按照hadoop1.2.1原版的hadoop-env.sh文件如下所示：

# Set Hadoop-specific environment variables here.

# The only required environment variable is JAVA_HOME.  All others are
# optional.  When running a distributed configuration it is best to
# set JAVA_HOME in this file, so that it is correctly defined on
# remote nodes.

# The java implementation to use.  Required.
# export JAVA_HOME=/usr/lib/j2sdk1.5-sun

# Extra Java CLASSPATH elements.  Optional.
# export HADOOP_CLASSPATH=

# The maximum amount of heap to use, in MB. Default is 1000.
# export HADOOP_HEAPSIZE=2000

# Extra Java runtime options.  Empty by default.
# export HADOOP_OPTS=-server

# Command specific options appended to HADOOP_OPTS when specified
export HADOOP_NAMENODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_NAMENODE_OPTS"
export HADOOP_SECONDARYNAMENODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_SECONDARYNAMENODE_OPTS"
export HADOOP_DATANODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_DATANODE_OPTS"
export HADOOP_BALANCER_OPTS="-Dcom.sun.management.jmxremote $HADOOP_BALANCER_OPTS"
export HADOOP_JOBTRACKER_OPTS="-Dcom.sun.management.jmxremote $HADOOP_JOBTRACKER_OPTS"
# export HADOOP_TASKTRACKER_OPTS=
# The following applies to multiple commands (fs, dfs, fsck, distcp etc)
# export HADOOP_CLIENT_OPTS

# Extra ssh options.  Empty by default.
# export HADOOP_SSH_OPTS="-o ConnectTimeout=1 -o SendEnv=HADOOP_CONF_DIR"

# Where log files are stored.  $HADOOP_HOME/logs by default.
# export HADOOP_LOG_DIR=${HADOOP_HOME}/logs

# File naming remote slave hosts.  $HADOOP_HOME/conf/slaves by default.
# export HADOOP_SLAVES=${HADOOP_HOME}/conf/slaves

# host:path where hadoop code should be rsync'd from.  Unset by default.
# export HADOOP_MASTER=master:/home/$USER/src/hadoop

# Seconds to sleep between slave commands.  Unset by default.  This
# can be useful in large clusters, where, e.g., slave rsyncs can
# otherwise arrive faster than the master can service them.
# export HADOOP_SLAVE_SLEEP=0.1

# The directory where pid files are stored. /tmp by default.
# NOTE: this should be set to a directory that can only be written to by 
#       the users that are going to run the hadoop daemons.  Otherwise there is
#       the potential for a symlink attack.
# export HADOOP_PID_DIR=/var/hadoop/pids

# A string representing this instance of hadoop. $USER by default.
# export HADOOP_IDENT_STRING=$USER

# The scheduling priority for daemon processes.  See 'man nice'.
# export HADOOP_NICENESS=10

对比发现其不同的地方基本在于：

# Command specific options appended to HADOOP_OPTS when specified
export HADOOP_NAMENODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_NAMENODE_OPTS"
export HADOOP_SECONDARYNAMENODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_SECONDARYNAMENODE_OPTS"
export HADOOP_DATANODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_DATANODE_OPTS"
export HADOOP_BALANCER_OPTS="-Dcom.sun.management.jmxremote $HADOOP_BALANCER_OPTS"
export HADOOP_JOBTRACKER_OPTS="-Dcom.sun.management.jmxremote $HADOOP_JOBTRACKER_OPTS"

于是修改hadoop-env.sh文件，使用easyhadoop的setup重新push即可（不要忘记修改JAVA_HOME配置）。

完整版本如下：

# Set Hadoop-specific environment variables here.

# The only required environment variable is JAVA_HOME. All others are
# optional. When running a distributed configuration it is best to
# set JAVA_HOME in this file, so that it is correctly defined on
# remote nodes.

# The java implementation to use.
export JAVA_HOME=/usr/java/default
 export HADOOP_C

# The maximum amount of heap to use, in MB. Default is 1000.
#export HADOOP_HEAPSIZE=
#export HADOOP_NAMENODE_INIT_HEAPSIZE=""

# Extra Java runtime options. Empty by default.
#export HADOOP_OPTS="-Djava.net.preferIPv4Stack=true $HADOOP_CLIENT_OPTS"

# Command specific options appended to HADOOP_OPTS when specified

export HADOOP_NAMENODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_NAMENODE_OPTS"
export HADOOP_SECONDARYNAMENODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_SECONDARYNAMENODE_OPTS"
export HADOOP_DATANODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_DATANODE_OPTS"
export HADOOP_BALANCER_OPTS="-Dcom.sun.management.jmxremote $HADOOP_BALANCER_OPTS"
export HADOOP_JOBTRACKER_OPTS="-Dcom.sun.management.jmxremote $HADOOP_JOBTRACKER_OPTS"

# The following applies to multiple commands (fs, dfs, fsck, distcp etc)
export HADOOP_CLIENT_OPTS="-Xmx256m $HADOOP_CLIENT_OPTS"
#HADOOP_JAVA_PLATFORM_OPTS="-XX:-UsePerfData $HADOOP_JAVA_PLATFORM_OPTS"

# On secure datanodes, user to run the datanode as after dropping privileges
export HADOOP_SECURE_DN_USER=

# Where log files are stored. $HADOOP_HOME/logs by default.
export HADOOP_LOG_DIR=/var/log/hadoop/$USER

# Where log files are stored in the secure data environment.
export HADOOP_SECURE_DN_LOG_DIR=/var/log/hadoop/

修改后，配置按照默认情况，在50070界面看到cluster summary如下：

2651 files and directories, 1117 blocks = 3768 total. Heap Size is 103 MB / 888.94 MB (11%)

这个是按照默认heapsize为1000的情况，修改hadoop-env.sh中的HADOOP_HEAPSIZE为500，可以看到cluster summary如下：

2651 files and directories, 1117 blocks = 3768 total. Heap Size is 72.88 MB / 444.5 MB (16%) 500

说明修改heapsize可以修改集群的heapsize了。

在上面提到的一篇国外的链接中，讨论了heapsize的 两个值到底代表什么意思。最后一个代表最大的heapsize，但是/前面的值代表什么意思？在集群运行Job的时候这个值也没有改变，这点在国外的链接中也没有给出详细介绍。

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