Help Center/ MapReduce Service/ User Guide/ Alarm Reference (Applicable to MRS 3.x)/ ALM-23004 Loader Heap Memory Usage Exceeds the Threshold
Updated on 2023-05-15 GMT+08:00
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ALM-23004 Loader Heap Memory Usage Exceeds the Threshold

Description

The system checks the heap memory usage of the Loader service every 60 seconds. The alarm is generated when the heap memory usage of a Loader instance exceeds the threshold (95% of the maximum memory) for 10 consecutive times. The alarm is cleared when the heap memory usage is less than the threshold.

Attribute

Alarm ID

Alarm Severity

Automatically Cleared

23004

Major

Yes

Parameters

Name

Meaning

Source

Specifies the cluster for which the alarm is generated.

ServiceName

Specifies the service for which the alarm is generated.

RoleName

Specifies the role for which the alarm is generated.

HostName

Specifies the host for which the alarm is generated.

Trigger Condition

Specifies the threshold triggering the alarm. If the current indicator value exceeds this threshold, the alarm is generated.

Impact on the System

The heap memory overflow may cause a service breakdown.

Possible Causes

The heap memory of the Loader instance is overused or the heap memory is inappropriately allocated.

Procedure

Check heap memory usage.

  1. On the FusionInsight Manager portal, choose O&M > Alarm > Alarms > Loader Heap Memory Usage Exceeds the Threshold > Location. Check the host name of the instance involved in this alarm.
  2. On the FusionInsight Manager portal, choose Cluster > Name of the desired cluster > Services > Loader > Instance. Click the instance for which the alarm is generated to go to the page for the instance. Click the drop-down menu in the chart area and choose Customize > Memory > Loader Heap Memory Resource Percentage. Click OK.

    Figure 1 Loader Heap Memory Resource Percentage

  3. Check whether the used heap memory of Loader reaches the threshold (the default value is 95% of the maximum heap memory) specified for Loader.

    • If yes, go to 4.
    • If no, go to 6.

  4. On the FusionInsight Manager portal, choose Cluster > Name of the desired cluster > Services > Loader > Configurations. Click All Configurations. Increase the value of -Xmx in GC_OPTS as required, and click Save. Click OK.

    • If this alarm is generated, the heap memory configured for the current Loader instance is insufficient for data transmission. You are advised to open the instance monitoring page, display the Loader heap memory resource status monitoring chart, and observe the change trend of the heap memory used by Loader in the monitoring chart. Then change the value of -Xmx to twice the current heap memory usage or to another value to meet site requirements.
    • When setting the heap memory, you can set -Xms and -Xmx to similar values to avoid performance deterioration caused by heap size adjustment after each GC.
    • Ensure that the sum of -Xmx and XX:MaxPermSize is not greater than the physical memory of the node server.

  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 fault information.

  1. On the FusionInsight Manager portal, choose O&M > Log > Download.
  2. Select Loader in the required cluster from the Service drop-down list.
  3. Click 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.
  4. Contact the O&M personnel and send the collected fault logs.

Alarm Clearing

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

Related Information

None