Buffalo TeraStation TS3420DN review: A NAS you can trust

A functional NAS with great 2.5GbE performance and data protection features at a very reasonable price

IT Pro Recommended
£550 exc VAT (4TB)
  • Great value
  • Fantastic performance
  • Top-notch security
  • No snapshot functionality
  • No third-party apps

Small businesses with big data-transfer needs will love Buffalo’s TeraStation TS3420DN. It’s an affordable four-bay desktop NAS appliance that supports 2.5GbE, providing more than twice the speed of a regular gigabit connection over legacy Cat5e network cabling. 

The price shown above is for our review model, which came with four 1TB Seagate IronWolf SATA drives in hot-swap carriers behind the lockable front door, and Buffalo also offers the appliance in 8TB, 16TB and 32GB capacities. There’s no diskless option, but the standard three-year warranty also covers the supplied drives: if a drive fails, just call Buffalo before 12 noon and its VIP service will furnish you with a new drive and carrier within 24 hours.

Drives aside, the core specification comprises a quad-core 1.4GHz Annapurna Alpine AL214 CPU and 1GB of non-upgradeable DDR3 memory. The 2.5GbE port is partnered by a standard gigabit one, plus a pair of USB 3 ports for attaching external storage devices.

Setup is almost instant: the NAS Navigator 2 Windows utility discovered the TS3420DN as soon as we connected it to our network, prompted us to set the admin password and offered options to change the array type, in case the preconfigured RAID5 arrangement didn’t suit our needs. 

Access control and security are well covered. You can decide which protocols each share should be accessible over, set up local user and group lists and optionally integrate with Active Directory. For extra protection, shares can be set as globally read-only, and to minimise the risk of malware getting onto the system, not even the administrative account has root rights. This is great news from a security standpoint, although it does reduce the versatility of the appliance, as third-party apps can’t be installed. 

Another smart security measure is Buffalo’s free Boot Authentication Tool, which protects your data if the appliance is stolen. Simply install this on a separate Windows host on your network, and the appliance will check for its presence during boot; if it’s not found, it will lock access to the web interface and all shares.

One feature that’s notably missing is snapshots, but for everyday data protection the onboard Backup app can duplicate data to remote Buffalo appliances (or any other rsync-compliant NAS appliance). It can also back up your data to Amazon S3 cloud buckets, and file-syncing apps are provided for Azure, Dropbox and OneDrive accounts. Workstation backup is taken care of by a bundled licence for NovaStor NovaBackup 19 software, which covers one Windows server and ten workstations. On-device antivirus scanning can be activated too, courtesy of Trend Micro, with a three-year subscription costing around £145. 

With the appliance’s 2.5GbE port connected to a Netgear ProSafe MS510TX Multi-Gigabit switch, we found the NAS performed very well. From a Dell PowerEdge T640 Xeon Scalable Windows server connected to the switch’s 10GbE port, Iometer recorded sequential read and write rates of 2.3Gbits/sec and 2.2Gbits/sec.

Real-world speeds are also very satisfactory, with drag-and-drop copies of a 25GB file completing at averages of 2.3Gbits/sec (read) and 1.9Gbits/sec (write). To test backup speeds, we copied a 22.4GB folder with 10,500 small files to the share, and this averaged 1.1Gbits/sec.

For IP SANs, we found file-based volumes deliver the best performance: with a 500GB target, we saw a read rate of 2.3Gbits/sec and a 2.2Gbits/sec write rate. Block-based volumes gave us the same read speeds, but a significantly lower 1.4Gbits/sec write rate.

The TS3420DN is ideal for small businesses that want affordable, uncomplicated network storage at multi-gigabit speeds. The app selection is minimal, but a strong set of backup and security services make this an appliance you can confidently entrust with your irreplaceable data. 

Buffalo TeraStation TS3420DN specifications   


Desktop chassis, 170 x 235 x 218mm (WDH)  


1.4GHz Annapurna Alpine AL214 CPU  


1GB DDR3 (maximum 1GB)


4 x 1TB Seagate IronWolf hot-swap hard disks



RAID support

RAID0, 1, 10, 5, 6 


Supports Gigabit Ethernet and 2.5GbE ports

Other ports

2 x USB 3


NovaBackup Buffalo Edition software (1 server, 10 desktops)


3yr VIP warranty

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