Synology RackStation RS4017xs+ Review

Synology’s RS4017xs+ is its largest NAS appliance to date and its first 3U 16-bay rack mount model. Aimed at storage-hungry SMBs, it supports low-cost, high-capacity SATA drives and looks a good choice as a big backup repository or surveillance vault.

The RS4017xs+ is also one of its most powerful general-purpose appliances as it comes with an 8-core 2.1GHz D-1541 Xeon CPU. The price includes 8GB of DDR4 UDIMM memory which can be boosted to a very usable 64GB.

Expansion potential isn’t up with Synology’s SAS-based appliances as although the RS4017xs+ has dual embedded Infiniband ports, they only support one disk shelf apiece. With a pair of 12-bay RX1217 shelves in the mix, you can push capacity to 40 drives – the RS18017xs+ supports seven shelves and up to 180 drives.

RS4017xs+ rear

Cooling, power and ports

The RS4017xs+ is well built with three 8cms diameter hot-plug cooling fans under a separate, removable cover in the lid. We found the appliance was reasonably quiet for general light usage but the fans ramped up noticeably during our heavy IOPS tests.

Power redundancy is covered as the price includes two hefty 800W hot-plug PSUs. Port options look good as well with the motherboard sprouting quad embedded Gigabit and dual 10GBase-T ports.

Two spare PCI-Express slots are up for grabs and support industry standard Intel and Emulex 10GbE adapters. Synology also offers its own single and dual-port 10GbE adapters while speed freaks can fit a Mellanox dual-port 40GbE card.

IHM – nearly

For testing, we fitted a quartet of 10TB Seagate IronWolf drives and let the quick start wizard create a big 27TB RAID5 array for us. Other options include dual-redundant RAID6 but Synology no longer supports its Hybrid arrays on its big business appliances.

Synology has collaborated with Seagate and its latest DSM 6.1 software introduces the IHM (IronWolf Health Management) feature. It automatically detects IronWolf drives to provide enhanced drive monitoring and more accurate drive failure predictions.

Accessed from the DSM Storage Manager app, IHM also provides options to run on-demand and scheduled health tests on selected drives. There’s just one glitch as it only currently supports IronWolf and IronWolf Pro drives up to 8TB capacities with Synology advising us that 10TB drive support will be added later on.

Speedy NAS performer

The appliance’s uprated CPU made its presence felt in our 10GbE performance tests as Iometer reported raw read and write speeds for a mapped share of 9.2Gbps and 8.4Gbps. Its mettle showed through in our I/O throughput test as with Iometer set to small 4KB transfer requests, we saw very good read and write rates of 136,000 IOPS and 92,000 IOPS.

The RS4017xs+ stayed the course with two servers in the mix as we recorded cumulative Iometer read and write rates of 18.4Gbps and 14Gbps. The I/O performance test also returned high cumulative read and write throughputs of 270,000 IOPS and 151,000 IOPS.

Real world speeds are also good with drag and drop copies of a 25GB test file returning average read and write speeds of 5.2Gbps and 3.8Gbps. The RS4017xs+ works for us as a general backup repository with our 22.4GB test folder and its 10,500 small files secured to a share at 2.2Gbps.

Better backup

synology 2

The new Active Backup app can run agentless backups of shares on Windows and Linux hosts

You’ll be hard pushed to find a better set of data protection and backup services than those offered in Synology’s latest DSM 6.1. BTRFS volumes brings NAS share and iSCSI LUN snapshots into play where you use the Snapshot Replication app to run them manually or schedule them as often as every five minutes.

It’s also used to replicate snapshots to remote Synology appliances that support BTRFS. Recovery options are extensive as we could restore or clone a share or LUN from the selected snapshot and use the File Station app to browse share snapshots and select individual files and folders.

Workstation backup is handled by the Cloud Station Server app with the Backup Windows workstation client providing one-way synchronization. Using the Cloud Station Drive on workstations allows two-way synchronizations to be performed.

Turn your appliance into a domain controller with the new Active Directory Server app

Turn your appliance into a domain controller with the new Active Directory Server app

If you don’t want to load a client on your workstations then try the new Active Backup app which just requires their IP address and user credentials to secure shared drives or directories to the appliance. Jobs can be scheduled to run regularly but don’t set too many for the same time as it can only run them sequentially.

More new apps

The versatile Hyper Backup app runs integrity checks to make sure it can recover your data

The versatile Hyper Backup app runs integrity checks to make sure it can recover your data

Currently in beta, the new Active Directory Server app teams up with the DNS Server app to turn your NAS appliance into a complete Samba-powered domain controller. All basic Windows AD features are present including users, groups and Kerberos authentication while login policies can be used to enforce password usage and run scripts.

The High Availability Manager (HAM) app has been updated to support S.M.A.R.T. tests and a quorum server but is still a very expensive failover solution. It supports an active/passive architecture so your secondary appliance will spend most of its time doing nothing and all storage services are stopped during the failover process.

The Hyper Backup app gets even more useful features as it can run integrity checks on backups and offers basic file-level deduplication. There’s more to snapshots as well as these can now be replicated to local volumes for extra on-site copies and run on encrypted volumes.


The RS4017xs+ is a great choice for SMBs that want a big network data repository using low-cost SATA hard disks and is better value than Qnap’s 16-bay TS-EC1680U R2. Expansion potential isn’t as good as Synology’s more expensive SAS-based appliances but it makes up for this with a super NAS performance over 10GbE and the latest DSM 6.1 software won’t be faulted for features either.

Build Quality
  • Sixteen SATA drive bays
  • Speedy NAS performer
  • Classy data protection apps
  • Good price
  • Only supports two disk shelves
  • IHM doesnt currently support 10TB drives

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