ALM-12205 Wait Duration of a Disk Write Exceeds the Threshold

Alarm Description

The system checks the wait duration of a disk write every 30 seconds and compares the actual wait duration with the threshold. This alarm is generated when the wait duration exceeds the threshold (10s by default) for multiple consecutive times.

This alarm is cleared when the wait duration is less than or equal to the threshold.

Alarm Attributes

Alarm ID	Alarm Severity	Alarm Type	Service Type	Auto Cleared
12205	Major	Physical resource	FusionInsight Manager	Yes

Alarm Parameters

Type	Parameter	Description
Location Information	Source	Specifies the cluster or system for which the alarm was generated.
	ServiceName	Specifies the service for which the alarm was generated.
	RoleName	Specifies the role for which the alarm was generated.
	HostName	Specifies the host for which the alarm was generated.
Additional Information	Trigger Condition	Specifies the alarm triggering condition.

Impact on the System

Latency: Service processes may run slowly and there is a latency.
Service failure: Service processing may be slow, time out, or fail. As a result, jobs may fail to run.

Possible Causes

The alarm threshold or alarm trigger count is improperly configured.
The disk configuration cannot meet service requirements. The disk I/O performance reaches the upper limit. Alternatively, services are in peak hours. The wait duration of a disk write reaches the upper limit in a short period.

Handling Procedure

Check whether the alarm threshold or alarm trigger count is properly configured.

Modify the alarm threshold and alarm trigger count based on the actual disk I/O usage.
1. Log in to FusionInsight Manager and choose O&M > Alarm > Thresholds > Name of the desired cluster > Host > Disk > Average Time Required for Each Write Operation.
2. Click the edit button next to Trigger Count to set it a proper value based on the actual service usage.
  
  Trigger Count indicates how many consecutive times the threshold is reached when the alarm is triggered.
3. Click Modify in the Operation column of the row that contains the rule and change the alarm threshold.
Wait 2 minutes and check whether the alarm is automatically cleared.
- If yes, no further action is required.
- If no, go to 3.

Check whether the average time required for each write operation reaches the upper limit.

On FusionInsight Manager, choose O&M > Alarm > Alarms. In the alarm list, expand the alarm details and click the name of the host for which the alarm is generated in Location area.
On the overview page of the host, observe the real-time data of average time required for each write operation for about 5 minutes. If the wait duration exceeds the threshold for multiple times, contact the MRS cluster administrator to improve the disk specification.

If the Average Time Required for Each Write Operation chart is not displayed, click the drop-down arrow on the right, select Customize, select the desired item, and click OK.
Check whether it was the peak hour. If this alarm was generated during peak hours, expand the node capacity or contact the MRS cluster administrator to improve the disk specification.
Check whether the alarm is cleared.
- If yes, no further action is required.
- If no, go to 7.

Collect fault information.

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