Configuring Memory Management¶
Scenario¶
In HDFS, each file object needs to register corresponding information in the NameNode and occupies certain storage space. As the number of files increases, if the original memory space cannot store the corresponding information, you need to change the memory size.
Configuration Description¶
Navigation path for setting parameters:
Go to the All Configurations page of HDFS by referring to Modifying Cluster Service Configuration Parameters.
Parameter | Description | Default Value |
|---|---|---|
GC_PROFILE | The NameNode memory size depends on the size of FsImage, which can be calculated based on the following formula: FsImage size = Number of files x 900 bytes. You can estimate the memory size of the NameNode of HDFS based on the calculation result. The value range of this parameter is as follows:
| custom |
GC_OPTS | JVM parameter used for garbage collection (GC). This parameter is valid only when GC_PROFILE is set to custom. Ensure that the GC_OPT parameter is set correctly. Otherwise, the process will fail to be started. Important NOTICE: Exercise caution when you modify the configuration. If the configuration is incorrect, the services are unavailable. | -Xms2G -Xmx4G -XX:NewSize=128M -XX:MaxNewSize=256M -XX:MetaspaceSize=128M -XX:MaxMetaspaceSize=128M -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled -XX:CMSInitiatingOccupancyFraction=65 -XX:+PrintGCDetails -Dsun.rmi.dgc.client.gcInterval=0x7FFFFFFFFFFFFFE -Dsun.rmi.dgc.server.gcInterval=0x7FFFFFFFFFFFFFE -XX:-OmitStackTraceInFastThrow -XX:+PrintGCDateStamps -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=1M -Djdk.tls.ephemeralDHKeySize=2048 |