Configuring NameNode Memory Parameters

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.

Procedure

1. Log in to FusionInsight Manager.

   For details about how to log in to FusionInsight Manager, see Accessing MRS Manager.

2. Choose Cluster > Services > HDFS > Configurations > All Configurations.
3. Search for the following parameters and change the parameter values under HDFS -> NameNode as required.

   Table 1 Parameters

   Parameter	Description	Example Value
   GC_PROFILE	Specifies the memory size of the garbage collection (GC). 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 following lists the values of this parameter and the corresponding memory size. high: 4 GB medium: 2 GB low: 256 MB custom: The memory size can be set according to the data size in GC_OPTS.	custom
   GC_OPTS	Configures garbage collection (GC). It is a common JVM option parameter. You can customize the configuration. This parameter is valid only when GC_PROFILE is set to custom. Ensure that the GC_OPTS parameter is set correctly. Otherwise, the process will fail to be started. CAUTION: Exercise caution when you modify the configuration. If the configuration is incorrect, the services are unavailable.	-

4. Click Save. Go to the Instances page and check whether there are instances whose configurations have expired. If yes, select the instances and choose More > Restart Instance. The configurations take effect after the restart.