Configure a custom vCenter alarm for APD or PDL events.

Products

• VMware vSphere ESXi

Issue/Introduction

• In a VMware vSphere environment, losing connectivity to storage is a critical issue. All Paths Down (APD) and Permanent Device Loss (PDL) represent two of the most severe storage states, often leading to VM unresponsiveness and datastore inaccessibility. To ensure system administrators are alerted immediately to these high-priority events, vCenter Server allows for the creation of specific alarms. This guide details the steps required to create an event-based alarm that triggers upon an APD or PDL condition.

Environment

VMware vSphere ESXi

Resolution

Creating APD or PDL Alarm -

1. In vCenter, navigate to the "Alarm Definitions", by selecting your vCenter object > Configure > Alarm Definitions > Add.

2. Add alarm name, definition and condition for the custom alarm -

• • To configure APD Alarm
    
    
    • Set the Alarm Name to "[Action] APD Detected on host." , the Description to "Alarm gets triggered upon observing 'esx.problem.storage.apd.start' event." the Target type to "Hosts", and then click "Next".
      
      
      
      
    • In the IF condition text field, add "esx.problem.storage.apd.start" or "All paths are down" and press Enter twice to configure the trigger for APD events. By configuring these values, we want the vCenter to detect below log entries on the host -
      
      Example :
      
      In "/var/run/log/vobd.log", you will see these events.
      
      2025-10-15T05:13:54.037Z In(14) vobd[2098144]:  [APDCorrelator] 4270429788920us: [esx.problem.storage.apd.start] Device or filesystem with identifier [eui.################################] has entered the All Paths Down state.

      
      
    • Select the severity as a "Warning", then select "Next".
      
      
      Note: Enable the toggle to send email/SNMP/script notifications, or use "ADD ADVANCED ACTIONS" to define host operations like "Enter maintenance mode" when the alarm triggers.
      
      
    • Review all the options you have selected and then select "CREATE".
      

 

Note: Similarly, you can configure a PDL alarm, and the only change is the IF condition value, where you simply have to replace "esx.problem.storage.apd.start" with "esx.problem.vob.vsan.pdl.offline", "vSAN device has gone offline." (if the host is using vSAN datastore) or "Device has been removed or is permanently inaccessible".

Additional Information

Create or Edit Alarms

Custom Alarms creation to track Datastore File downloads from vCenter server

vCenter alarm at the Virtual Machine layer to alert if a VM is running on a snapshot to prevent the datastore running out of space.

Setting an alarm for virtual machine hard disk usage

Using the VMkernel Observations for Creating Alarms