Connecting Multiple NASs to One UPS

by Ray Newbery in

If you have a NAS you need to protect it with a UPS (Uninterruptible Power Supply). They provide both battery backup and protection from electrical spikes or sags. If you have multiple Synology NASs there’s no need for multiple Uninterruptible Power Supplies. With just a little planning you can save some money and run multiple NASs off the same UPS.


The requirements are simple, there’s no special hardware required.

  1. You’ll want a UPS that’s supported by Synology, and most major brands are.
  2. You’ll want a UPS that has enough power reserve for your needs. This will vary depending on the number of NASs that you protect and how big they are. The main power draw is the number of drives with spinning hard drives drawing more power than solid state drives. I have a 1350VA/810 Watt UPS that will key three Synology NASs running with 12 spinning drives and two SSDs going for well over 30 minutes.
  3. You’ll need a network switch (or hub) that has enough network ports for each NAS that is connected to the UPS.
  4. The UPS needs enough power outlets with battery backup for each NAS, plus one more for the network switch.
  5. The NASs plus your network switch (or hub) that the NASs connect to all need to be within a power cable’s reach of the UPS.

You want the network switch (or hub) plugged into the same UPS and the NAS since they will use this switch to communicate with the UPS. If the switch loses power before the NAS shuts down it (the NAS) will not receive the shutdown order before the battery runs dry. You can connect it to a second UPS but this introduces a potential complication that may prevent a NAS shutdown.


Plug all the NAS power cables into battery protected outlets on the UPS. Plug the switch into a battery protected outlet on the same UPS. If you have a power brick that will block multiple outlets you can use a short extension cord.

Pick one Synology NAS to be the UPS server. This should be a NAS that is powered on whenever the other NASs are. For example, I have three NASs but only one is always on so it is the UPS server.

Enable the UPS Server

Go to the UPS tab in the Hardware & Power section of Control Panel in DSM. Check the boxes to Enable UPS Support and to Enable Network UP Server.

Enabling the UPS Server in DSM

Click the Permitted DiskStation devices button and enter the IP addresses for your other UPS. You can get this from the Info Center section of Control Panel on each of those NASs.

Permitting UPS clients in DSM

Click OK and Apply as needed to save all your settings.

Get the IP Address of this NAS (your UPS server). You can get this from the Info Center section of Control Panel.

Enable the UPS Client

On the other NASs go to the UPS tab in the Hardware & Power section of Control Panel in DSM. Check the box to Enable UPS Support then select Synology UPS Server as the Network UPS Type. Enter the Network UPS Server’s IP address.

Enabling the UPS client in DSM

When you click Apply DSM will verify the connection to the UPS. If it can’t find the UPS server it will display an error message.

Checking the UPS

You can click Device Information on any UPS Server or Client to check the status of the UPS and get an estimate on the time remaining.

Checking the UPS status in DSM