ALM-45439 ClickHouse Node Enters the Read-Only Mode

Alarm Description

The system checks the disk capacity of the ClickHouseServer node every 1 minute. This alarm is generated when the system detects that the disk capacity exceeds 90% and the ClickHouseServer node enters the read-only mode.

This alarm is automatically cleared when the system detects that the disk capacity is lower than 90% and the ClickHouseServer node exits the read-only mode.

If the ClickHouseServer node is in read-only mode and you need to log in to the client to clear data, you can manually exit the read-only mode using the following method:

Log in to FusionInsight Manager, choose Cluster > Services > ClickHouse > Configurations > All Configurations, search for profiles.default.readonly, and change its value to 0.

Alarm Attributes

Alarm ID	Alarm Severity	Auto Cleared
45439	Major	Yes

Alarm Parameters

Parameter	Description
Source	Specifies the cluster or system 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.
DiskPath	Specifies the path of the disk for which the alarm is generated.

Impact on the System

After the ClickHouseServer node enters the read-only mode, all write, modification, and deletion operations fail.

Possible Causes

The disk usage of the ClickHouse node exceeds 90%.

Handling Procedure

Log in to FusionInsight Manager, choose O&M > Alarm > Alarms, and view the role name and the IP address for the hostname in Location.
Expand the disk capacity of the node for which the alarm is generated.
Go to 4 if the expansion fails or the alarm persists after the expansion.

After the capacity expansion, this alarm can be automatically cleared only when profiles.default.readonly is auto. If its value has been manually changed, change it back to auto. If profiles.default.readonly needs to be set to 0 or 1 based on service requirements, manually clear this alarm.

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, and select ClickHouse for the target cluster.
Expand the Hosts drop-down list. In the Select Host dialog box that is displayed, select the abnormal host, and click OK.
Click the edit icon in the upper right corner, and set Start Date and End Date for log collection to 1 hour ahead of and after the alarm generation time, respectively. Then, click Download.
Contact O&M personnel and provide the collected logs.