ALM-14030 HDFS Allows Write of Single-Replica Data

Alarm Description

This alarm is generated when dfs.single.replication.enable is set to true, indicating that HDFS is configured to allow write of single-replica data.

This alarm is cleared when this function is disabled on HDFS.

Alarm Attributes

Alarm ID	Alarm Severity	Alarm Type	Service Type	Auto Cleared
14030	Major	Quality of service	HDFS	Yes

Alarm Parameters

Type	Parameter	Description
Location Information	Source	Specifies the cluster 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

Data of a single replica may be lost. Therefore, the system does not allow write of single-replica data by default. If this configuration is enabled on HDFS and the number of HDFS replicas configured on the client is 1, single-replica data can be written to HDFS.

Possible Causes

The HDFS configuration item dfs.single.replication.enable is set to true.

Handling Procedure

Log in to FusionInsight Manager and choose Cluster > Services > HDFS. On the page that is displayed, click the Configurations tab then the All Configurations sub-tab.
Search for dfs.single.replication.enable in the search box, change the value of the configuration item to false, and click Save.
On the Dashboard page of the HDFS service, click More and select Service Rolling Restart in the upper right corner.
After the HDFS service is started, check whether the alarm is cleared.
- If yes, no further action is required.
- If no, go to 5.

Collect fault information.

On FusionInsight Manager, choose O&M. In the navigation pane on the left, choose Log > Download.
Expand the drop-down list next to the Service field. In the Services dialog box that is displayed, select HDFS for the target cluster.
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.
Contact O&M engineers and provide the collected logs.