ALM-14030 HDFS Allows Write of Single-Replica Data

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.

Attribute

Parameters

Impact on the System

If this configuration is enabled on the server and the number of HDFS replicas configured on the client is 1, single-replica data can be written to HDFS. Data of a single replica may be lost. Therefore, the system does not allow write of single-replica data by default. If a service requires single-replica data write to a directory, modify the HDFS configuration item dfs.single.replication.exclude.pattern.

Possible Causes

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

Procedure

1. Log in to MRS Manager and choose Cluster > Services > HDFS. On the page that is displayed, click the Configurations tab then the All Configurations sub-tab.
2. Search for dfs.single.replication.enable in the search box, change the value of the configuration item to false, and click Save.
3. Wait for about 10 minutes and check whether the alarm is cleared.
   • If yes, no further action is required.
   • If no, go to 4.

Collect fault information.

4. On MRS Manager, choose O&M. In the navigation pane on the left, choose Log > Download.
5. Expand the drop-down list next to the Service field. In the Services dialog box that is displayed, select HDFS for the target cluster.
6. 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.
7. Contact O&M personnel and provide the collected logs.

Alarm Clearing

This alarm is automatically cleared after the fault is rectified.

Related Information

None