This example demonstrates a useful type of alarm action that you might configure for an object in the vSphere inventory, including responding to the alarm when it triggers.

Dozens of default alarm definitions are provided by the vSphere Client, which you can locate in the Alarms tab for an inventory object. One of these default alarms is Datastore usage on disk, which you use to monitor the percentage of disk usage. This kind of alarm is important if the virtual machines in the datastore have virtual disks in the thin provisioned format. With thin provisioning, at first a thin provisioned disk uses only as much datastore space as the disk initially needs. However, if the thin disk needs more space later, it can grow to the maximum capacity allocated to it.

With thin provisioning, it is possible to oversubscribe storage space if the virtual machines grow unattended. An alarm set on the datastore can notify you when the space issues threaten to become critical.

This example demonstrates how to modify the Datastore usage on disk alarm to send emails when certain thresholds are reached.


VMware recommends that you first experiment with the procedures presented in vSphere Examples and Scenarios on test instances in your datacenter.

Someone who is assigned the Administrator role can configure alarms. Alarm privileges do not appear in other default sample roles accessible with the vSphere Client. To create a unique role for this process that does not include all the privileges of an Administrator, the following list contains the minimum privileges necessary.

Alarms.Create alarm

Alarms.Modify alarm

Alarms.Acknowledge alarm

For information about roles, permissions, and privileges, see the vSphere Security documentation.