"Alert:" "Data Disk usage has exceeded the predefined threshold" appearing on the Warning tab of a Postgres database instance in DSM

Products

• VMware Data Services Manager for VCF

Issue/Introduction

Symptoms: 

• Within the VMware Data Services Manager (DSM) 9.0.1 console, a "Data disk Health alert" is displayed on the Warning tab for a provisioned Postgres database instance. 
  
  Alert: "Data disk Health alert" "Data Disk usage has exceeded the predefined threshold"
  
  

• Data Disk Size was configured to be 200GIB. can be validated under Databases > <DB-to-Monitor> > Summary > Infrastructure > Edit > Disk size
  
  
  
  
  
• As defined in the DSM architectural specifications, a health notification is generated when usage reaches the 70% threshold (Example: 140 GB for a 200 GB disk). 
• Can be validated under Databases > <DB-to-Monitor> > Alert Threshold

• If the current usage of exceeds 140 GB, the alert is expected behavior. 
• The Data Disk Usage can be validated under Databases > <DB-to-Monitor> > Monitor > Metrics > Data Disk Usage

Environment

DSM 9.x 

Cause

This alert represents expected operational behavior within the DSM architecture. VMware Data Services Manager is pre-configured with a default "Soft Threshold" for disk utilization set at 70%.
When a database instance's storage consumption exceeds this baseline threshold, the system automatically triggers a health notification. This is designed to preemptively alert administrators to potential capacity exhaustion before it impacts database performance or uptime.

Resolution

To remediate the alert and clear the warning, administrators must provision additional storage capacity to the affected database instance. Expanding the disk increases the total available block space, which consequently reduces the overall utilization percentage below the 70% soft threshold.

Perform the following steps to dynamically expand the disk capacity:

1. Authenticate to the VMware Data Services Manager (DSM) Management Console.

2. Navigate to the Databases directory and select the affected Postgres instance.

3. Prerequisite: Verify within vCenter that the underlying database virtual machine currently has no active snapshots, as snapshots will block disk expansion.

4. Locate the Infrastructure section and select Edit.

5. Increase the Disk Size parameter to a value that provides sufficient operational headroom (for example, scaling from 200 GB to 300 GB).

6. Select Save to apply the configuration change.

Once the storage expansion completes, the DSM system will recalculate the disk utilization percentage. The health alert will automatically clear once the usage drops below the 70% threshold.

Additional Information

For further details on monitoring database metrics, refer to the official documentation:

• Viewing Database Status in the VMware Data Services Manager Console