Help Center > > User Guide> FusionInsight Manager Operation Guide> Alarm Reference (Applicable to MRS 3.x)> ALM-45284 UserSync Garbage Collection (GC) Time Exceeds the Threshold

ALM-45284 UserSync Garbage Collection (GC) Time Exceeds the Threshold

Updated at: Mar 25, 2021 GMT+08:00

Description

The system checks the GC duration of the UserSync process every 60 seconds. This alarm is generated when the GC duration of the UserSync process exceeds the threshold (12 seconds by default) for five consecutive times. This alarm is cleared when the GC duration is less than the threshold.

Attributes

Alarm ID

Alarm Severity

Automatically Cleared

45284

Major

Yes

Parameters

Name

Meaning

Source

Cluster for which the alarm is generated.

ServiceName

Service for which the alarm is generated.

RoleName

Role for which the alarm is generated.

HostName

Host for which the alarm is generated.

Trigger Condition

Threshold for triggering the alarm.

Impact on the System

UserSync responds slowly.

Possible Causes

The heap memory of the UserSync instance is overused or the heap memory is inappropriately allocated. As a result, GCs occur frequently.

Procedure

Check the GC time.

  1. On FusionInsight Manager, choose O&M > Alarm > Alarms > ALM-45284 UserSync Garbage Collection (GC) Time Exceeds the Threshold. Check the location information of the alarm and view the host name of the instance for which the alarm is generated.
  2. On FusionInsight Manager, choose Cluster > Services > Ranger > Instance. Select the role corresponding to the host name of the instance for which the alarm is generated and click the drop-down list in the upper right corner of the chart area. Choose Customize > GC > UserSync GC Duration. Click OK.
  3. Check whether the GC duration of the UserSync process collected every minute exceeds the threshold (12 seconds by default).

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

  4. On FusionInsight Manager, choose Cluster > Services > Ranger > Instance > UserSync > Instance Configuration. Click All Configurations, and choose UserSync > System. Increase the value of -Xmx in the GC_OPTS parameter based on the site requirements and save the configuration.

    If this alarm is generated, the heap memory configured for UserSync cannot meet the heap memory required by the UserSync process. You are advised to change the -Xmx value of GC_OPTS to the twice that of the heap memory used by UserSync. You can change the value based on the actual service scenario. For details about how to check the UserSync heap memory usage, see 2.

  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.

  1. On FusionInsight Manager, choose O&M > Log > Download.
  2. Expand the Service drop-down list, and select Ranger for the target cluster.
  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 O&M personnel and provide the collected logs.

Alarm Clearing

After the fault that triggers the alarm is rectified, the alarm is automatically cleared.

Related Information

None

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