Synology SA3400 review: A big NAS for big businesses

A powerful performer with a high storage capacity and backup features galore

IT Pro Verdict

Synology’s SA3400 is a versatile and powerful rack NAS well-suited to business duties such as backup, virtualisation and surveillance


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    SAS3/SATA support

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    Good value

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    Fast 10GbE performance

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    Wealth of data protection apps

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    High memory capacity


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    Noisy cooling fans

Coming in as the replacement for Synology's RS18017xs+ NAS appliance, the SA3400 aims to deliver a big boost in features and performance. It's the first in Synology's line of enterprise-class SA' appliances where the new naming convention indicates support for SAS3 and SATA storage.

There's a lot more on offer than just SAS3 support though. This 2U 12-bay rack NAS sports an 8-core 2.1GHz Xeon D-1541 CPU, teamed up with 16GB of server-grade DDR4 ECC RDIMM memory which can be upgraded to a healthy 128GB. The discontinued RS18017xs+ supports SAS3 storage but has a six-core 2.2GHz Xeon D-1531 and slower 2,133MHz DDR4 memory.

Port-wise, there are no changes as the SA3400 also provides quad Gigabit and a pair of 10GBaseT. The two rear USB 3 ports can be used to add extra storage devices while an external SAS port supports seven RX1217sas or RX2417sas expansion shelves for a maximum of 180 drives.

Synology SA3400 review: Design and expansion

The SA3400 exhibits the classy build quality we've come to expect from Synology, presented as it is in a sturdy steel chassis. The metal drive carriers can't be key locked but a small tab on each one can be pushed across to stop them being accidentally popped out.

Cracking the lid reveals a tidy interior with the Xeon CPU mounted by a large passive heatsink and partnered by four DIMM slots, with the base memory provided on a single 16GB stick. All storage is managed by a Synology SAS12G PCIe card, which provides the external SAS expansion port and is cabled directly to the drive backplane.

Two PCIe slots are free for further expansion, and the SA3400 supports a good range of industry-standard 10GbE, 25GbE and 40GbE network adapters. We tested this with a dual-port Emulex 10GBaseT adapter, which was accepted without any problems

Cooling is handled by a bank of four hot-plug fans behind the drive backplane with a solid air shroud directing air from the centre two fans over the CPU. Noise levels are intrusive though, as even on the slowest fan setting, we recorded high sound levels of 66.5dB at one metre in front of the appliance.

Synology SA3400 review: Great 10GbE performance

For performance testing, we installed four 16TB Seagate Exos X16 enterprise SATA hard disks, ran Synology's web-based discovery wizard and created a 44TB RAID5 storage pool. With the appliance hooked up over 10GbE to a Dell PowerEdge T640 Xeon Scalable tower running Windows Server 2019, we saw a mapped NAS share return fast Iometer sequential read and write speeds both of 9.3Gbits/sec.

The good news continued with our real-world tests as copies of a 25GB test file delivered read and write rates of 5.6Gbits/sec and 5Gbits/sec. Our backup test was also handled well with a 22.4GB folder holding 10,500 small files secured to the share at a speedy 2.5Gbits/sec.

IP SAN speeds are equally impressive; a 1TB iSCSI target delivered Iometer read and write rates both of 9.3Gbits/sec. We ramped up the pressure with a dual 10GbE MPIO link and saw speeds increase nicely to 18.5Gbits/sec and 17.1Gbits/sec all with the appliance's CPU snoozing at 15% utilisation.

Synology SA3400 review: Classy backup apps

If you're looking for top-quality data protection and backup features, then look no further: Synology's DSM software is brimming with apps. The Snapshot Replication app supports manual and scheduled NAS and IP SAN snapshots on BTRFS volumes and offers fast recovery services, which include the option to browse NAS snapshots and restore files directly from the File Station app.

Synology's Active Backup for Business (ABB) app takes data protection to the next level, providing a central location for securing servers, workstations and virtual environments. It supports agentless backup services for VMware vCentre and ESXi hypervisors, provides application-consistent backups of virtual machines (VMs) and best of all, it's completely free.

After loading the ABB agents on our Windows servers and workstations, we could schedule volume, file and bare-metal backups. Recovery features are outstanding as you can recreate systems as VMware VMs or use the ABB web portal for swift file and folder restores.

The Hyper Backup app presents a single console for managing local, remote, Rsync, cloud and iSCSI LUN backups and it integrates with Synology's C2 Backup cloud service for off-site storage. The Drive app also provides Dropbox-like sync services for Windows workstations plus iOS and Android mobiles with the Drive agent loaded.

Synology SA3400 review: Virtualisation and surveillance

The SA3400's high capacity makes it a fine candidate for running Synology's Surveillance Station 8.2 app. It supports over 7,200 IP camera models, offers a wealth of video recording and playback tools and can enforce secure dual-authentication access to recordings.

You can even turn your iOS or Android mobile into an IP camera with the LiveCam app which sends live video and audio streams directly to the Surveillance Station console and records them. It's easy to use as well: simply enter the appliance's address in the LiveCam app on your mobile, log in and tap the Play button.

The Virtual Machine Manager (VMM) app adds extra versatility as it allows the appliance to host VMs running any OS you fancy. We created a Windows Server 2019 VM in 15 minutes, presented it on a dedicated virtual switch created from the appliance's Gigabit ports and used the app's built-in protection plans to take regular snapshot backups.

Synology SA3400 review: Verdict

For a 12-bay NAS appliance that supports SAS3 and SATA storage, the SA3400 is comparatively good value. NAS and iSCSI performance over 10GbE is impeccable, it has plenty of room to expand and Synology's DSM software offers a remarkable range of features including plenty of free backup apps.

Synology SA3400 specifications

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Chassis2U rack
CPUEight-core 2.1GHz Xeon D-1541
Memory16GB 2,400MHz ECC RDIMM DDR4 (max 128GB)
Storage12 x LFF/SFF SAS3/SATA hot-swap bays
Array supportRAID F1, 0, 1, 10, 5, 6, JBOD
Expansion2 x PCI-e Gen3
Network4 x Gigabit, 2 x 10GBaseT
Power2 x 500W hot-plug PSUs
ManagementWeb browser
Warranty5 years limited
Dave Mitchell

Dave is an IT consultant and freelance journalist specialising in hands-on reviews of computer networking products covering all market sectors from small businesses to enterprises. Founder of Binary Testing Ltd – the UK’s premier independent network testing laboratory - Dave has over 45 years of experience in the IT industry.

Dave has produced many thousands of in-depth business networking product reviews from his lab which have been reproduced globally. Writing for ITPro and its sister title, PC Pro, he covers all areas of business IT infrastructure, including servers, storage, network security, data protection, cloud, infrastructure and services.