ALM-45588 IoTDBServer Direct Memory Usage Exceeds the Threshold

Alarm Description

The system checks the direct memory usage of the IoTDBServer service every 60 seconds. This alarm is generated when the direct memory usage of the IoTDBServer instance exceeds the threshold for five consecutive times. This alarm is cleared when the IoTDBServer direct memory usage is less than or equal to the threshold.

Alarm Attributes

Alarm Parameters

Impact on the System

Direct memory overflow may cause service breakdown.

Possible Causes

The direct memory of the IoTDBServer process is overused or the direct memory is inappropriately allocated.

Handling Procedure

Check the direct memory usage.

1. Log in to FusionInsight Manager and choose O&M. In the navigation pane on the left, choose Alarm > Alarms. On the page that is displayed, locate the row containing the alarm whose Alarm ID is 45588, view the role name in Location, and check the instance IP address.
2. Choose Cluster > Name of the desired cluster > Service > IoTDB > Instance. Click the IoTDBServer for which the alarm is generated to go to Dashboard. Click the drop-down list in the upper right corner of the chart area and choose Customize > Memory. In the dialog box that is displayed, select IoTDBServer Direct Buffer Resource Percentage, and click OK.
3. Check whether the direct memory used by the IoTDBServer reaches the threshold (90% of the maximum direct memory by default).
   • If yes, go to 4.
   • If no, go to 6.

4. On FusionInsight Manager, choose Cluster > Name of the desired cluster > Service > IoTDB > Configuration, click All Configurations, choose IoTDBServer > System, increase the value of -XX:MaxDirectMemorySize in the GC_OPTS parameter as required, and save the configuration.
   

   • If this alarm is generated, the direct memory configured for the IoTDBServer process cannot meet the requirements of the IoTDBServer process.
   • You are advised to set -XX:MaxDirectMemorySize in GC_OPTS to twice the direct memory used by the IoTDBServer process. (You can change the value based on the actual service scenario.)
   • To obtain the size of the direct memory used by the IoTDBServer process, choose Customize > Memory > IoTDBServer Direct Memory Resource Status. If GC_OPTS does not contain the -XX:MaxDirectMemorySize parameter, add it manually.

5. Restart the affected services or instances and check whether the alarm is cleared.
   • If yes, no further action is required.
   • If no, go to 6.

Collect the fault information.

6. On FusionInsight Manager, choose O&M. In the navigation pane on the left, choose Log > Download.
7. Expand the Service drop-down list, and select IoTDBServer for the target cluster.
8. 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.
9. Contact O&M engineers and provide the collected logs.

Alarm Clearance

This alarm is automatically cleared after the fault is rectified.

Related Information

None.