Your Synology NAS might well be a critical component of your home or business network, storing valuable data, media, and backups. But have you considered what happens during a power outage? A sudden loss of power can lead to data corruption, hardware damage, and service interruptions, which can be difficult to come back from especially if you don't have a proper backup solution in place. This is where an uninterruptible power supply (UPS) comes in, and why it's generally a good idea to have one.

For the uninitated, think of a UPS as a giant powerbank and a surge protector all in one. It evens out the power coming in from your electrical grid, protects your hardware against surges, and keeps your devices running when the power goes out.

Why you should get a UPS for your NAS

There are a few benefits

First things first, you don't necessarily need a UPS, but it's undoubtedly a good thing to have. Unexpected shutdowns can leave your NAS in an inconsistent state, potentially corrupting files or databases. Even with built-in protections like Btrfs snapshots or RAID redundancy, an abrupt power loss can still cause significant data integrity issues.

Not only that, but sudden shutdowns can put stress on its components, most notably the hard drives or the power supply. Over time, repeated power fluctuations can shorten the lifespan of your hardware, even if problems aren't apparent immediately after an outage. This can also damage your services on a software level, as if you have any important services running when the outage occurs, files may be saved improperly, causing corruption or other problems.

Finally, RAID rebuilds can take hours, and a power failure during a rebuild can lead to catastrophic data loss. This is quite rare, and most of the time when you come back online the worst thing that will happen is it restarts the process from 0%, but it's really not worth the risk. If you live in a place that has regular power outages, a UPS is almost certainly a requirement. This is especially because file systems like Btrfs rely on proper shutdown sequences to avoid errors.

What you need in a UPS for your NAS

What do you use your NAS for?

When it comes to buying a UPS, there are a few things you need to check. The most important is its capacity, as you'll want to ensure that it can keep your NAS running for a little bit to give it time to finish what it's doing and shutdown, so you'll be looking to get at least a couple of minutes out of it. Synology has built-in support for compatible UPS devices, as when the UPS is powering it, it will start to unmount drives and safely shut down.

You'll need to make sure that the UPS you want to buy actually works with Synology's DSM operating system. These will typically be plugged into a USB port, and you can enable UPS support in the Synology control panel so that it can then react to information your UPS gives it. As well, if you experience longer outages, a UPS with a bigger capacity might be better.

Finally, you'll want to weigh up the additional features you can get, in case any are important to you. Specifically, you can look for UPS devices with automatic voltage regulation (AVR), LCD displays, and network management capabilities if you require advanced monitoring and control.

Not everyone needs a UPS, but it's nice to have

Especially if you have frequent power cuts

I wouldn't say that everyone needs a UPS, but it's undoubtedly nice to have and can save you in a pinch. While one power outage isn't likely to cause problems, it still can, and a UPS could save you in that instance. If you experience frequent power outages, though, then it's a borderline necessity.

A UPS essentially means you can ensure your NAS remains reliable and secure even in the event of power disruptions, and for some people, that's more than worth it. Keep in mind that if your power goes out, chances are your NAS won't have an internet connection either, but most NAS software will give you the ability to configure how it reacts to a power outage.