4 reasons you shouldn’t expand your NAS storage with USB drives

When populating your network-attached storage (NAS) with drives, it’s important to consider hard disk drives (HDDs) and solid-state drives (SSDs). These are excellent for reliably storing lots of data and are specifically designed for use inside NAS devices. Another medium that can be used to expand your NAS’s capacity is the trusty USB drive. Many prebuilt turnkey NAS enclosures have a few USB ports available, but here are some reasons why you shouldn’t rely on USB drives for storing data long-term.

4 Only available in limited capacities

USB drives suffer from similar issues to standard SSDs and don’t offer as many capacities as hard drives. A NAS HDD can be bought with a capacity of up to 24TB. SSDs are slowly catching up with the most expensive drives coming in at 8TB but USB flash drives are even lower at 2TB. That’s not a lot compared to standard-sized drives in bays. Although 2TB sounds like a lot, you’ll rely on the number of available USB ports on the NAS. Once they’re all populated, you’ve reached the limit. Using USB ports also limits what else you can do with the NAS, including connecting a keyboard and/or mouse.

3 USB drives aren’t designed for storage pools

USB drives aren’t designed for storing data as part of a pool. If you’re running ZFS, things can become interesting when performing drive-intensive operations such as a scrub or resilver. There’s a higher chance the USB drive will fail before an HDD or SSD. The internal parts within USB drives don’t tend to be as advanced or expensive, especially compared to NAS-grade storage drives. And suing USB ports to expand your storage capacity can cause issues when working with USB hubs. It can prove difficult to determine which port is which. Finally, there’s no support for S.M.A.R.T.

2 Not physically secured to the NAS

NAS enclosures are precisely that. An enclosure to protect the drives running within. It’s also why we spend a lot on a PC case to ensure everything inside the system operates as designed and is protected against the elements. The same cannot be said for USB flash drives as they connect to external USB ports on the device. The same goes for NAS where the ports can be on the front or rear of the unit. Relying on a USB flash drive to increase the storage pool is one thing, but making sure no one accidentally removes it from the NAS is a whole different ball game.

1 USB ports are slower

USB ports have come a long way with the latest standard offering bandwidth up to 20 Gbps. For context, the latest Thunderbolt 5 can hit speeds of 80 Gbps. A NAS enclosure may only have one port that can hit 5 or 10 Gbps with perhaps an additional two that can’t even hit 1 Gbps. USB ports are therefore slow and you won’t see them fully saturated by connected USB flash drives. A SATA III slot inside the NAS will have a 6 Gbps rated speed and M.2 SSDs are even faster, depending on the CPU and available PCIe lanes.

Use only HDDs and SSDs inside NAS

USB drives have their place in your storage world. They’re excellent for installing operating systems (and running them, like Unraid), but they shouldn’t be used as part of a storage pool, no matter how many precautions you take. They’re not as reliable, fast, or long-lasting as other drives. You could accidentally disconnect one mid-operation, and they’re not great value compared to larger mechanical drives. Stick to full-size drives for storing data and use USB drives to move data, backup configuration files, and take data off-site.

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