ALM-14020 Number of Entries in the HDFS Directory Exceeds the Threshold

Alarm Description

The system obtains the number of subfiles and subdirectories in a specified directory every hour and checks whether it reaches the percentage of the threshold (the maximum number of subfiles and subdirectories in an HDFS directory, the threshold for triggering an alarm is 90% by default). If it exceeds the percentage of the threshold, an alarm is triggered.

When the number of subfiles and subdirectories in the directory the alarm is lower than the percentage of the threshold, the alarm is automatically cleared. When the monitoring switch is disabled, alarms corresponding to all directories are cleared. If a directory is removed from the monitoring list, alarms corresponding to the directory are cleared.

• The dfs.namenode.fs-limits.max-directory-items parameter specifies the maximum number of subfiles and subdirectories in the HDFS directory. Its default value is 1048576. If the number of subfiles and subdirectories in a directory exceeds the parameter value, subfiles and subdirectories cannot be created in the directory.
• The dfs.namenode.directory-items.monitor parameter specifies the list of directories to be monitored. Its default value is /tmp,/mr-history.
• The dfs.namenode.directory-items.monitor.enabled parameter is used to enable or disable the monitoring switch. Its default value is true, which means the monitoring switch is enabled by default.

Alarm Attributes

Alarm Parameters

Impact on the System

If the number of entries in the monitored directory exceeds 90% of the threshold, an alarm is triggered, but entries can be added to the directory. Once the maximum threshold is exceeded, entries will fail to be added to the directory.

Possible Causes

The number of entries in the monitored directory exceeds 90% of the threshold.

Handling Procedure

Check whether unnecessary files exist in the system.

1. Log in to the HDFS client as user root. Run the cd command to go to the client installation directory, and run the source bigdata_env command to set the environment variables.

   If the cluster is in security mode, security authentication is required.

   Run the kinit hdfs command and enter the password as prompted. Obtain the password from the administrator.

2. Run the following command to check whether files and directories in the directory with the alarm can be deleted:

   hdfs dfs -ls Directory with the alarm

   • If yes, go to 3.
   • If no, go to 5.

3. Run the following command to delete unnecessary files.

   hdfs dfs -rm -r -f File or directory path

   

   Deleting a file or folder is a high-risk operation. Ensure that the file or folder is no longer required before performing this operation.

4. Wait 1 hour and check whether the alarm is cleared.
   • If yes, no further action is required.
   • If no, go to 5.

Check whether the threshold is correctly configured.

5. On the FusionInsight Manager portal, choose Cluster > Name of the desired cluster > Services > HDFS > Configurations > All Configurations. Search for the dfs.namenode.fs-limits.max-directory-items parameter and check whether the parameter value is appropriate.
   • If yes, go to 9.
   • If no, go to 6.

6. Increase the parameter value.
7. Save the configuration and click Dashboard > More > Restart Service.
8. Wait 1 hour and check whether the alarm is cleared.
   • If yes, no further action is required.
   • If no, go to 9.

Collect fault information.

9. On the FusionInsight Manager portal, choose O&M > Log > Download.
10. Select HDFS in the required cluster from the Service.
11. Click the edit icon in the upper right corner, and set Start Date and End Date for log collection to 10 minutes ahead of and after the alarm generation time, respectively. Then, click Download.
12. Contact the O&M engineers and send the collected logs.

Alarm Clearance

After the fault is rectified, the system automatically clears this alarm.

Related Information

None.