Question CyberPower CP1350AVRLCD3

[USAFRet]

When the power goes out, what is the difference between

1. Turn off the server after the AC power fails
2. The system will enter “auto-protection” mode after the AC power fails

https://docs.qnap.com/operating-system/qts/4.2.x/cat2/en-us/index.html?ups.htm

By enabling UPS (Uninterruptible Power Supply) support, you can protect your NAS from abnormal system shutdown caused by power disruption. There are two options provided on the "UPS" page for the NAS during a power failure: 1) turn off the server after the AC power fails, or 2) enter the auto-protection mode after the AC power fails. For option 1, the NAS will shut itself down after the specified time. For option 2, the NAS will stop all running services and unmount all volumes to protect your data after the specified time. For details on NAS behavior during a power failure, refer to the "Behavior of the UPS Feature of the NAS" section. Please note that to protect your data, once the power outage starts, the NAS will automatically turn itself off or enter auto-protection mode (depending on your settings) after 30 seconds regardless of the specified time for either of the above options if the remaining UPS battery charge is < 15%.

 

[velocci]

https://docs.qnap.com/operating-system/qts/4.2.x/cat2/en-us/index.html?ups.htm

but what is the benefit of unmounting the volumes before it turns off?

 

[USAFRet]

but what is the benefit of unmounting the volumes before it turns off?

Prevents potential file/data corruption.

A sudden "off" may corrupt a file that is in write status at that moment.
Or if the NAS is doing any of its other internal cleanup.

Unmounting clears all of that before power off.

 

[velocci]

Prevents potential file/data corruption.

A sudden "off" may corrupt a file that is in write status at that moment.
Or if the NAS is doing any of its other internal cleanup.

Unmounting clears all of that before power off.

But when you choose to turn off the nas when the power goes out, the nas stops all services and does a proper shutdown. It shouldn’t corrupt and files.