Review: Synology DS1815+ Review

Introduction

Aimed at both business and home users in need of gigantic amounts of storage, the DS1815+ is an eight-bay NAS from Synology, powered by a quad-core CPU and up to 6GB of memory. This places it at the very opposite end of the performance scale from the single-bay DS115J that came out late last year.

With a retail cost of around £850 (US$1030, AU$132) it's at the upper end of NAS pricing, although one step below the level occupied by rack-mount NAS units, such as the Thecus NN810U-G or Synology's 12-bay RackStation RS3614xs+.

There's space for eight hot-swappable 3.5-inch or 2.5-inch disks, which offers up to 48TB of internal storage (when using 6TB hard disks) and this can be extended further by purchasing a pair of external five-bay DX513 modules, which connect to the unit's two eSATA ports at the back. Therefore, if you need it, the DS1815+ offers up to 108TB of storage space. The DS1815+ also support hardware-based encryption of your entire file system.

It has four gigabit ethernet ports, which can be configured for redundancy in case of failure, or together via link aggregation to offer up to 4Gbit/sec of bandwidth. And as with any Synology NAS, it comes with DiskStation Manager, the company's excellent Linux-based NAS operating system, which currently sits at version 5.1.

Appearance and design

If you're familiar with Synology's NAS range, the DS1815+ will be instantly recognisable, as it looks just about identical to the DS1813+. The unit measures 340mm across, and comes in a very strong plastic case, which doesn't take up too much space under a desk or on a shelf. The eight removable bays are accessible at the front. At the bottom of each disk bay is a green status LED, with additional indicators for the LAN ports, an alert notifier and power at the top.

There are four USB 3 ports at the back along with the two eSATA ports, a pair of large fans and an internal power supply, so a standard "kettle" lead is all you need to get it up and running.

The DS1815+ is powered by a quad-core Intel Atom C2358 processor, which runs at 2.4GHz, a chip which should be enough to cope with many users simultaneously. There are two memory slots, one occupied by a 2GB DDR3 SODIMM as standard.

Disk installation is completely free of tools and screws. You secure the disk into the bay by pushing two black plastic strips into the mounting holes, pushing the disk into the units, then closing the plastic cover. To remove them, a quick press of the front pops the cover up and you can easily slide the disk out.

Since plastic can break, I thought it a good idea to look at how to replace a broken mounting bracket, if the need arose. Synology lists lots of spare parts on its website, but you can't order them directly. Instead the company says to locate a reseller, who should be able to help.

The trump card of all Synology's NAS products is DiskStation Manager, the excellent Linux-based operating system that powers them. It offers a familiar Windows-like environment, accessible via a browser, with groups of icons and menus to navigate around the system and widgets to provide at-a-glance information, such as internal temperature, CPU utilisation, and so on.

The software functions just about identically on the high-end model like the DS1815+ as it does the lower end units, but there are some subtle differences in what it can do.

If you set up a download manager for torrent files and so on, the number of concurrent downloads is limited with a NAS such as the DS115J, but the DS1815+ lets you run up to 80 at the same time.

Similarly, DiskStation Manager lets you run a web server from your NAS, with support for SQL databases, WordPress, Drupal, Joomla, and so on. With a low-end unit, the limited CPU and memory resources restricts what you can do. It might be useful as a development server, or for use on an intranet with a small number of clients, but with the beefed-up network and processing performance offered by the DS1815+, you can host a site with a larger number of users.

This is really just scratching the surface of DiskStation Manager. As well as full domain and Active Directory support, there's a built-in firewall, Telnet, SSH, FTP, iSCSI, all sorts of traditional RAID modes in addition to Synology Hybrid RAID, although not RAID 50 or 60, as with the Thecus N8810U-G.

And there are numerous plugins and software packages to extend the functionality of the DS1815+, accessible via a browser within DiskStation Manager.

Testing and setup

I filled the DS1815+ with eight WD Red 6TB hard disks, set up to use Synology Hybrid RAID. The build process finished in around 30 minutes, and after the software was updated I was ready to see what speeds I could get from it.

Early on I ran into what I consider to be a major performance issue, which applies to many NAS devices with multiple gigabit ethernet ports. Although the DS1815+ allows its four gigabit ethernet ports to be bonded together and used as a single connection, in order to get four times the usual gigabit speed when performing a single file transfer, your network switch must support both 802.3ad link aggregation and LACP, or dynamic link aggregation. Most modern managed switches support 802.3ad, but not all support LACP, as I discovered.

When the DS1815+ is first powered on, each port is assigned a separate IP address. When they're bonded together in the DiskStation Manager software, the unit only needs a single address, but you'll only get standard gigabit speeds via any single transfer. There's still a performance advantage though, because with up to four clients transferring files at the same time, the DS1815+ can provide a full 1Gbit/sec to each client.

For the full 4Gbit/sec speed from a single transfer, you'll need to adjust the configuration of your switch to bond those ports together into a LAG group. Unmanaged cheap desktop switches don't even have any configuration software, so you'll need to look at a managed switch. While common in small business environments, they're hardly an essential home networking purchase, and this feature isn't exactly common on routers either.

The first two switches I tried supported 802.3ad, but not LACP. When the ports were bonded together in the switch software, the DS1815+ reported in red text that it "could not enable 802.3ad link aggregation". It then dropped off the network and was inaccessible. It was only when I borrowed a more high-end HP ProCurve switch that I could get the DS1815+ working at full speed.


And obviously, with four ethernet ports, you'll need four cables, along with four network cards in your client PC, with another four cables connecting the PC to the switch, for a total of eight. Savvy network admins use colour-coded cabling for troubleshooting, perhaps using one colour for cabling from the NAS and another for cabling to the NAS.

Another aspect of full-speed use to consider is software. Bonding connections together in Windows isn't straightforward. The only modern operating system that allows you to do so natively is Windows Server 2012, which might be overkill for a home setup. Otherwise, you'll need to use cards that support link aggregation in the drivers.

This limitation isn't a total show-stopping issue. When used in a business environment with many clients, providing a good speed to multiple users is more useful than a single user gobbling up all the bandwidth, but these extra hardware requirements are worth bearing in mind.

I tested the capabilities of the DS1815+ using Intel's NAS performance toolkit and a standard Windows file transfer of 5GB folders of both large and small files. I could only test the full speed using a file transfer though, since my time with the HP ProCurve switch was limited.

At standard gigabit speeds, the DS1815+ is a leap ahead of its predecessor, and shows excellent performance in small file transfers, particularly in tests that put strain on the CPU.

Synology DS1815+ Results (single port)

Intel NAS Performance Toolkit:

• HD Video Playback91.4 MB/s


• 2x HD Playback98.7 MB/s


• 4x HD Playback99.6 MB/s


• HD Video Record108.3 MB/s


• HD Playback and Record101 MB/s


• Content Creation11.7 MB/s


• Office Productivity66.3 MB/s


• File copy to NAS116.1 MB/s


• File copy from NAS85.7 MB/s


• Dir copy to NAS23.6 MB/s


• Dir copy from NAS28.3 MB/s


• Photo Album12.1 MB/s

Synology DS1815+ Results (four ports):

• Small File Read148 MB/s


• Small File Write98 MB/s


• Large File Read398 MB/s


• Large File Write423 MB/s

Compared with other NAS units I've tested, these are good results. Of particular note are some of the individual tests within Intel's NAS performance toolkit, which rely on CPU performance, with 50-100 per cent better performance than NAS models with single or dual-core CPUs. Crucially, the DS1815+ is significantly faster than the quoted figures for the DS1813+ (which I haven't tested under identical conditions).

We Liked

The build quality and physical design of the DS1815+ are simply fantastic. With the notable exception of the bonded ethernet connections, it's really easy to set up and use. It's sturdy, quiet and arguably quite attractive too.

DiskStation Manager is still light years ahead of any competitor's software, in terms of both ease of use and the staggering amount of functions it offers. No rival can touch the interface design, although admittedly, plenty of competing NAS units offer a good array of software features as well.

The expandability is great to see too. Adding an additional 60TB of capacity without having to buy another NAS is something I can see many owners taking advantage of, since the entire volume will be accessible and managed from a single point, with a single set of security controls and so on.

We Disliked

The gaping hole in the feature list of the DS1815+ is 10GbE. Faffing around with LACP in your switch software and bonded connections and took a lot of time to get working. If you don't have a switch that supports this feature, you'll be stuck running it at standard gigabit ethernet speeds.

This is obviously a cost issue. The DS1815+ has been designed to be (relatively) affordable, and adding 10GbE hardware would have pushed the pricing close to the levels of larger NAS units. If you're considering the DS1815+ for home use, a switch that supports LACP is an additional expense you might need to consider.

When Synology designs a follow-up to the DS1815+, perhaps 10GbE prices will have dropped enough to warrant its inclusion. But right now, if you want 10GbE, you need to be looking at the next tier of NAS units.

While performance is mostly excellent, some results from the Intel NAS Performance Toolkit could have been slightly better. I had expected the quad-core CPU to chew through the Photo Album test, but it wasn't amazing, and was outclassed by the Thecus NN810U-G. This is possibly because while still a quad-core chip, the C2358 is only an Atom processor. However, the DS1815+ edges ahead of the NN810U-G in some of the other tests.

Verdict

The DS1815+ is an excellent NAS that can be used in many different ways. It offers enough performance to be used as a network server, running databases, web sites and so on. Equally, with up to 108TB of storage, the DS1815+ can be configured as a gargantuan file server, which may be of particular interest to media organisations, who might be shunting terabytes of 4K video around a network.

It fits perfectly between the NAS units aimed at home users, with two or four bays, and the really powerful enterprise models.

That said, it has its limits. The CPU is a step behind the Xeon processors you get with higher-end NAS units, and therefore under really heavy load the DS1815+ is no substitute for a real server. And in large enterprises, ECC memory might be required, which is not supported by Atom processors.

Running the four ethernet ports together as a single bonded connection is straightforward, as long as you have the required hardware. But without an LACP-capable switch, you're stuck on lower speeds. That might be a small additional expense to consider, but even with that added on top, the overall cost of the DS1815+ is far lower than a 10GbE-capable NAS.

Even with this in mind, the DS1815+ is a great upgrade from its predecessor and a strong performer. Unless your business has particularly demanding applications, it will serve you well.

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