UPS management

About UPS management

Data ONTAP enables you to register and monitor the status of UPS (Uninterruptible Power Supply) devices you are using with your storage system. In addition, you can configure the timing of certain Data ONTAP events when a power loss occurs.

About registering, enabling and disabling UPS devices

You use the ups command to register UPS devices with Data ONTAP, and to review their status. For more information about the ups command, see the na_ups(1) man page.

About the UPS shutdown options

Data ONTAP provides two configurable values to help you manage your storage system in case of a power outage:

warningtime
The warningtime option specifies when Data ONTAP generates a warning SNMP trap, AutoSupport message and log message.

The default value of the warningtime option is 300 seconds (5 minutes).
criticaltime
The criticaltime option specifies when Data ONTAP generates another SNMP trap, AutoSupport message and log message, and then starts shutting down the storage system.

The default value of the criticaltime option is 60 seconds (1 minute).

About the shutdown process

When a power loss occurs, the UPS device begins supplying power to your storage system from its batteries. The UPS can only supply power as long as its batteries still have enough charge; the UPS is there to give you time to shut down your storage system cleanly.

The shutdown process is outlined in the following tasks.

Note
If you do not have AutoSupport enabled, the AutoSupport messages will not be generated.

Step	Task
1	When the power loss occurs, an SNMP trap, AutoSupport message, and log messages are generated alerting you that the power loss has occurred.
2	When the UPS has `warningtime` seconds of battery life remaining, Data ONTAP generates another SNMP trap, AutoSupport message, and log message.
3	When the UPS has `criticaltime` seconds of battery life remaining, Data ONTAP generates another SNMP trap, AutoSupport message, and log message and starts shutting down the storage system. Note The `criticaltime` notifications may not be sent, depending on system load.

Step

Task

When the power loss occurs, an SNMP trap, AutoSupport message, and log messages are generated alerting you that the power loss has occurred.

When the UPS has warningtime seconds of battery life remaining, Data ONTAP generates another SNMP trap, AutoSupport message, and log message.

When the UPS has criticaltime seconds of battery life remaining, Data ONTAP generates another SNMP trap, AutoSupport message, and log message and starts shutting down the storage system.

Note
The criticaltime notifications may not be sent, depending on system load.

About using the default shutdown event timings

For many environments, you can simply use the default values of five minutes for warningtime and one minute for criticaltime. However, you are advised to make sure that these values are set appropriately for your environment to avoid any data loss in case of a power outage. The warningtime value should give you enough time to do whatever manual processes you need to do prior to system shutdown, and criticaltime should provide enough time for the system to shut down cleanly.

Factors that might influence shutdown event timing for your environment

Factors that can affect the optimal value of these options for your environment include:

UPS battery availability
If your UPS cannot support the default timing values, then your storage system will not be able to shut down cleanly.
Storage system workload
If you have a large number of users, a large number of CIFS sessions, or any other workload factors that require a longer time to shut down, you need to increase the warning and critical time values to ensure that the system has sufficient time to shut down cleanly.
Company policies and procedures
You may need to change the shutdown event timings to adhere to a protocol or requirement in place at your company.

Configuring the shutdown event timings

If, after reviewing this documentation, you decide that you need to change these values, you can do so using the registry command.

Note
You are strongly advised to contact technical support before changing the shutdown event timing values.