Synology Disk Station DS509+ Network Attached Storage Device Review

This solution promises PC server equivalent performance for efficient data sharing and backup. It is supposed to suit perfectly for cross platform sharing, secure server backup, Windows ADS integration, business mail server, and corporate surveillance. Read more in our review!

by Hugh Barros
08/26/2009 | 01:23 PM

Deservedly considered a leader of the Network Attached Storage market, Synology offers top-quality, high-performance and functional products. The company’s product range spans from home NASes for 1, 2 or 4 hard disks to professional rack-mounted or desktop solutions for up to 5 disks (or 10 disks with an extension module). Synology’s NASes are based on platforms with ARM or PPC processors although it is the x86 architecture that delivers the highest performance today. Notwithstanding this fact, Synology’s products, including top-end ones like the DS509+ I am going to talk about in this review, compete successfully with their opponents. The DS509+ differs from the junior models of the series only with the number of supported HDDs and amount of system memory, so it is going to have the same speed characteristics as the DS109+, DS209+, and DS409+. The functionality is the same, too. The different models have virtually identical firmware and the description below refers, except for minor details, to all of them.


You can visit the company’s website to check out a detailed comparison of the various NAS models from Synology. There are a lot of other online resources: a well-developed user community, FAQs, Wiki and blogs all supported by the manufacturer.

Package and Accessories

The device is intended for people who know for sure what they want, so the plain cardboard box measuring 36x32x29cm is quite appropriate packaging. It won’t be placed in storefronts for display, anyway. You can get a notion of the size and weight of the device by looking at the cut-in handles on the sides of the box. There is a plastic handle at the top, but you should not rely on it only. A small sticker reports you the model’s name, specs and accessories. There are no other decorations here.

Besides the NAS, the box contains HDD frames with screws (including spare screws) and a couple of keys, a CD, documentation, two Ethernet cables and a power cord.

The capabilities of a modern NAS change greatly with firmware updates, so there is no point in having a full user manual, but the manufacturer did not even include a simple setup guide. The included multilingual leaflet suggests that you visit the manufacturer’s website or read the PDF on the CD. This is normal for this kind of a device, though. I doubt that it will be used by beginner users.

But even if you consider yourself experienced, you may want to browse the quick start guide and the full user manual. They are available in electronic format.

The CD contains a few programs for different OSes:

It is good that the manufacturer thinks about users of alternative OSes. DSAssistant is required to write firmware to the NAS for the first time. The firmware image files can be found on the CD, too. Download Replicator makes it easy to work with the autonomous file download feature. Data Replicator is a simple backup tool. All of this is gathered together under Windows in a single auto-running shell that also offers links to the manuals and program installers. These programs can also be launched without installing on the computer’s hard disk, which is handy for the one-use DSAssistant or if you need to restore data on another PC using Data Replicator.

Exterior Design

Synology prefers to paint its professional NASes black. The DS509+ follows the same trend, its case being matte black on all sides, save for the bottom and back panel. The device is rather large at 22x20x17.5 centimeters, but that’s natural for a 5-disk model.

The front panel is made from robust black plastic. Most of it is occupied by the HDD bays which support hot swapping and can be locked with a key. Above the bays there are four indicators and a Power button with integrated LED. The indicators help you learn the status of the device, the connection and activity of its network interfaces. At the top of the bays there are a couple of status indicators for each HDD.

The DS509+ does not have a dot matrix display which is often installed in modern NASes.

The casing and the chassis of the device are made from metal and seem to be robust and reliable.

At the back panel you can find two 80x25mm cooling fans (SUNON KDE1208PTV3) and connectors: power connector, two LAN ports with indicators, two USB 2.0 ports, one eSATA port and a serial port. There is also a Reset button and a Kensington security slot here.

Note that there are only two USB ports here, both at the back panel. Perhaps that’s not crucial for a SOHO device, but opponent products can offer up to five USB and a couple of eSATA ports.

The quality of manufacture is overall very high.

Hardware Configuration

The case is sealed, meaning that the user is not meant to tinker with the internals of the device. This did not prevent me from getting into the thing, though.

A Seasonic SS-250SU power supply is located at the top of the case. Its peak output power of 250 watts is quite enough for powering the NAS’s electronic components together with five modern HDDs. The PSU is cooled with an individual 4cm cooler. Despite the suspicious form-factor, the fan is quiet. The NAS is overall not very loud, yet it is not the best option for a bedroom because five HDDs, even quiet ones, will produce an audible noise in the open bays. You may want to prefer “closed” models (for example, the DS409 or the DS209) for such usage.

With five HDDs inside, the NAS had the following power consumption:

The NAS’s hardware components reside on three PCBs: a main PCB, a backplane, and an indication unit. The main PCB carries the following:

This is the fastest platform currently used in Synology products. The Freescale mpc8533 processor has PPC architecture and is clocked at slightly above 1 gigahertz. This modern model comes with integrated controllers of PCIe and PCI buses, a 64-bit DDR/DDR2 memory controller, and two Gigabit Ethernet interfaces.

The NAS is equipped with two disk controllers from different makers to provide six SATA ports (five internal and one external port). That’s a queer solution, especially as one controller supports PCIe while the other PCI, yet there should be no difference in speed between them.

Your upgrade opportunities are limited to changing the memory module, but the default 1 gigabyte is quite enough for most applications.

Prep Work

First you install your HDDs on the frames and insert the frames into the NAS. Then you connect the network cable and the power cord, and the NAS is ready to go. You can turn it on and, after a short while, you will hear a sound signal and will be able to proceed to install firmware. With Synology NASes, the firmware is installed on a hard disk partition. To be exact, it is a mirror partition that is present on all the HDDs installed, so you should not worry about the firmware getting corrupt. The DS509+ takes about 2.5 gigabytes of storage space from each HDD for that purpose. The useful capacity is also diminished by the size of the swap file, which is half a gigabyte more.

For this test session I installed the latest available beta version of firmware (DSM 2.2 0914) using an appropriate version of DSAssistant (once the firmware is installed, you will be able to update it via the web-interface).

During the first installation you can specify such parameters as network addresses, integrated timer settings, administrator password. For multi-disk NASes you will have to create a volume (or a few volumes) for storing user data and public folders.

Synology’s web-interface is one of the handiest and prettiest on the market. Although its design has been revised lately, it is easy to learn the new positions of certain buttons.

The interface is available in several languages. The language is selected automatically according to your browser settings or specified by the user manually. You can also select the language for email letters and network clients that do not support Unicode. The pretty visuals are based on AJAX and your browser must support this technology. It means there can be problems with access from mobile devices.

If you log in as administrator, you can access all settings and features of the system. If you log in as a simple user, you will only be able to use those features (like the browser-based file access or file download station) that your access rights permit, check out the disk quote usage level and change your password.

Once you enter the interface, you can see all accessible services as icons on the first page.

Web interface access can be protected with SSL encryption and the standard ports 5000/5001 can be changed. Additional protection is provided by the automatic logoff timer.

Basic Functionality

The NAS has two Gigabit Ethernet controllers that support Jumbo Frames up to 9000 bytes for higher performance. Besides working as two independent interfaces, they can work together to increase bandwidth or reliability. The network controllers support DHCP or can be assigned static IP addresses. The NAS offers integrated PPPoE and DDNS clients. A firewall is available to improve security on large networks. It allows to specify access rights flexibly for each interface. To make it easier, there is a predefined list with all the integrated services.

The user can also enable the feature that automatically blocks clients attempting to guess the password. That’s quite a useful option for a NAS, I think.

For each installed HDD you can learn the model name and firmware version. The NAS offers integrated tools to test and view the SMART info of each HDD. The power management system can turn the HDDs off if they remain idle for a certain period of time.

You can find an HDD compatibility list at the manufacturer’s website. It is rather long including the newest 2TB models. There is also another list that is based on users’ feedback. I do recommend you to check those lists out before choosing and purchasing HDDs for this NAS.

You can unite up to five HDDs installed in this NAS into RAID arrays. JBOD, RAID0, RAID1, RAID5 (also with a hot swap disk) and RAID6 are supported whereas RAID10 is missing. You can enlarge the maximum amount of disk space twofold by means of an external rack called Synology DX5. It can accommodate five HDDs which are connected via a single eSATA cable to the DS509+.

It is quite easy to manage data volumes. You can perform some configuration changes without losing your data. For example, you can migrate from one HDD to RAID1 or RAID5 or from RAID1 to RAID5. You can increase the volume size of a RAID5 or RAID6 array by sequentially replacing its HDDs with larger-capacity ones or by adding new HDDs.

A failure of an HDD in a fault-tolerant array provokes a log entry (and an email/SMS notification if enabled), appropriate indication on the front panel, and a sound signal (can be turned off in the web-interface). If there is a spare HDD (only for RAID5), the recovery process begins automatically. Otherwise, the user has to replace the disk and launch the process via the web-interface. It took about 2 hours and a half to recover a RAID5 built out of five 500GB HDDs after one of them had been replaced.

Besides typical RAID arrays, the new firmware also supports iSCSI. An iSCSI volume is created on an existing array and can thus be fault-tolerant, too.

The speed of iSCSI is usually somewhat higher because it is direct block-based access with lower overhead. However, I could only achieve read and write speeds of 45 and 47MBps, respectively, with a volume located on one disk. Data-transfer rates can be higher with RAID arrays.

To implement all these functionality, the system uses software RAID and LVM technologies. The main file system of data volumes is EXT3. Unfortunately, the manufacturer does not provide the option for the user to check the file system out manually and correct any errors. Perhaps the NAS is indeed so reliable, yet I would like to have that option anyway.

It is a distinguishing feature of Synology’s products that they support all modern file access protocols including SMB/CIFS, AFP, NFS, FTP(S) and HTTP(S). The NAS supports peer-to-peer mode and domains on Windows networks. A network trash bin for deleted files can be turned on.

As for AFP implementation, the NAS offers full support for TimeMachine, the Mac OS X integrated backup tool. This is a highly useful feature and many Apple users require it from their NASes.

There is nothing special about NFS. It just works and may be useful for users of network media players which provide higher video bit-rates via NFS than via SMB.

The FTP settings are almost perfect. You can change all the ports, limit the number and speed of connections, use Unicode, enable connection encryption, etc.

The capabilities of the browser-based file manager will be discussed shortly.

Traditional entities such as users, groups and shared folders are used to provide access to files. There are quite a lot of parameters you can specify for users: name, password, email address, comment, group membership, disk quota (individually for each disk volume). You can prohibit a user to change his password or block access on specific days. User groups are used for easier assignment of rights and do not have special parameters of their own.

Public folders are created on ready disk volumes. A few names are reserved for system services (e.g. “music”, “photo” and “video” for the media server). Access rights (no access, read-only, read & write) are assigned by users (for SMB, FTP and AFP) or by IP-addresses (for NFS). Special rights can be applied to folders and files for FTP and HTTP access: prohibition to view the list of files, prohibition to change existing files, and prohibition to download a file.

For NFS, you can create a list of hosts and address ranges with individual rights.

The NAS allows to control individual users’ access to specific services such as FTP, HTTP-based access, file download station, and video surveillance.

Summing it up, I must acknowledge that the NAS’s basic functionality is implemented very well. It is going to work correctly with any types of client devices.

External Devices

The NAS has two USB and one eSATA port. This is not too many, but you can use USB hubs to have more USB ports whereas eSATA can work via a port multiplicator. Standard types of external devices are supported: external hard drives and flash drives, printers, UPSes.

The NAS can see the first partition of an HDD connected via eSATA. It is mounted into the public folder “satashare”. You can specify user rights for it and they will remain in effect when you connect another eSATA drive. FAT32, NTFS and EXT3 file systems are accessible for reading and writing. The same goes for USB drives. You can safely disconnect and format external HDDs in FAT32 and NTFS from the web-interface.

The NAS is fast with eSATA drives – nearly as fast as with the internal HDDs. The top speeds of reading and writing are 57/71MBps with EXT3. With NTFS, the speeds are somewhat lower at 42/32MBps. The NAS can support one or two printers and is compatible with most USB models. The compatibility list can be found at the company’s website. You cannot make full use of all-in-ones with the firmware I installed for my tests. It also does not allow to check out the level of ink in inkjet printers, for example.

The NAS mostly supports uninterruptible power supplies from APC. You can specify the time interval after the loss of mains power, and when this interval is over, the NAS switches to safe mode in which all its services are stopped and the data volumes are turned off. The NAS can be programmed to shut down automatically, too. Since an UPS can be connected to one control system only, the NAS offers a network UPS emulation system for environments with multiple NASes. That is, the NAS the UPS is directly connected to works as a server while the other NASes are clients. This allows to turn off multiple storage devices safely and simultaneously.

The NAS also supports iPhone/iPod Touch. After you install a free application called DS Audio from AppStore, you will be able to listen to music from the NAS.

System Settings

There is quite a lot of interesting things you can find among the NAS’s system settings beside the usual save/restore/reset configuration and firmware update.

The integrated timer with Internet synchronization and email notifications (for two recipients, with support for authorization and encryption) are standard settings, too. The SMS support is a rare setting but you have to subscribe to a paid service to use it. Clickatell settings are available, but they seem to be adaptable for other such providers. You can also keep track of the NAS’s operation via SNMP.

The system offers basic power management capabilities. Besides the turning off of the internal HDDs I mentioned above, the same option can be applied to external USB drives. You can shut the whole NAS down, too, and specify the time and day of week for turning it on and off. The wake-on-power option is going to be useful if you don’t have an UPS.

The logging feature is very advanced and handy. Besides the usual event logs, it allows to keep track of all actions of users of the FTP server and web-based file manager. You can also learn who is connected via network at this moment and check out the details of the data backup system.

Based on flash technology, the system monitoring panel shows load graphs for the CPU (indicating the most resource-consuming applications), system memory, network interfaces as well as the overall and occupied disk space. The status page is informative, too. It shows such information as model name, firmware version, serial number, disk status (including temperature) and data volume status, network settings, external devices, etc.

Additional Features

In our age of ubiquitous Internet, it is often necessary to access data using only a web-browser. This feature is supported by many modern NASes. Synology calls it File Station and this station is a full-featured file & folder manager that allows to download and upload files, create folders, rename and remove files and folders, copy and move data (also between different public folders). You can even change file access rights using that manager.

This service can be moved to an individual website by adding a new access port. When you type in the address, you will see a window to enter your name and password. You can also specify the name of the site, color scheme, and the logo in the top left corner. Like the other web services, this feature supports encrypted connections.

The NAS offers a few more browser-based services. Particularly, you can transform it into a web-server with php and MySQL (“Web Station”), listen to music in your browser or USB speakers using the Audio Station, or store photo albums with the Photo Station.

As opposed to similar services found in other NASes, the Photo Station is surprisingly functional. It has a separate user database, supports access rights, slideshows, comments to photos, blogs, calendar, statistics reporting and even interface customization. It would actually take a separate review to describe all its functionality.

As usual, iTunes and DLNA are supported, too. All these media services use network folders with predefined names: “photo”, “music”, and “video”. Unfortunately, you cannot add your own folders to them.

The iTunes server is based on the Firefly software, supports music files in MP3 and M4A formats and video files in MOV and MP4 formats. The program can index tags (and supports Unicode) and can work with user-defined play-lists (in M3U files or specified by filtering criteria).

The functionality of the UPnP AV media server has been enhanced in the newer firmware version. It has acquired DLNA certification, can index video files in mkv, ts, m2ts, mov, iso formats and is compatible with Windows Media Player. It can also read mp3 and m4a tags, has an integrated transcoder for flac, ogg, aac and aiff formats and supports wav/pcm. The player’s menu can be customized.

Here is the full list of supported formats: jpg, bmp, gif, tiff, png, mp3, aac/m4a, wma, ogg, wav, ac3, avi, divx, mp4, mpeg, mkv, wmv, mov, m2ts, ts, m4v, vob, iso. You can sort files by folder (for photos and videos) and by artist, album, genre (for music). Tags or folder names can be used for sorting out music. Summing it up, the only shortcoming I can see here is that the media server can only work with the predefined folders rather than with any folders you might specify.

It is no secret that NASes are often used to work with torrents. The DS509+ is not an exception. Synology’s Download Station is actually one of the most functional implementations that but rarely calls for replacement with an alternative client. Besides FTP, HTTP, BitTorrent and eMule, it now supports NZB, RapidShare and even RSS. As for setup options, you can choose ports, limit speeds, enable DHT and encryption, download specific files from a torrent, seed files by a schedule or upon reaching a certain rating (individually for each download). The maximum number of simultaneous downloads is 20. If that doesn’t satisfy you, you will have to install another client. However, this should be quite enough for not-very-fast Internet connections, especially as you can manage download tasks by pausing, restarting and removing them. The Download Station can work by a schedule and send notifications about complete downloads.

The DS509+ has integrated data backup tools. I mean the option of creating backup tasks to make copies of data in shared folders. The recipient can be a local folder (also on an external disk), a second NAS from Synology, or any standard rsync server. Backup tasks can be launched in manual mode or by a schedule. Data can be restored via the web-interface.

Video surveillance is yet another task the DS509+ can perform. It has been enhanced greatly in the beta version firmware I used. You can now flexibly configure live-view windows and use handier tools to control the watching of recordings. The list of compatible camera models has been enlarged. The DS509+ now supports RTP translations of MJPEG and MPEG4 streams, SMS notifications and a larger number of video cameras simultaneously.

The DS509+ model can work with a dozen cameras but comes with a license for only one camera. You have to pay extra to enable the NAS to work with more cameras. The DS509+ supports most modern cameras working with MJPEG and MPEG4 codecs. You can assign access rights to system users: each can be an administrator or a viewer. Email and SMS notifications are supported and the settings (server, recipients) may differ from those of the NAS’s own notification settings. The recording modes are defined by a weekly per-hour schedule: constant recording, motion sensor (the integrated motion sensor can only work with MJPEG).


Functionality Enhancements

Synology is one of the first makers that opened access to the integrated OS via a console. On one hand, a user’s tinkering with console commands can damage the device (for example, if the boot-loader is erased in the flash memory), but on the other hand, this opens infinite opportunities in enhancing the device’s functionality. The DS509+ also allows to enable telnet and SSH in the web-interface, and you can then access the device as a super-user. Following the description at the manufacturer’s WiKi site, you can install the optware package manager and use the various programs available through it. This requires some basic knowledge of Linux from the user but there is a safer way of installing new services. You can install ready-made packages from the manufacturer. At the current moment, four programs are available: a server for Squeezebox devices (to broadcast audio recordings), an email server, a module to display statistics for the web-services, and phpMyAdmin. The setup pages of the new services are integrated into the NAS’s main interface. Besides SMTP and POP3, the email server supports IMAP, encrypted versions of the protocols, and even offers a web-based client interface for browser access.

Frankly speaking, there is nothing in the NAS’s default functionality that calls for changes. Still, if you miss anything, you can add that quite easily.


I tested the performance of the NAS using Intel NASPT 1.7.0, which replays prerecorded traces of different tasks. I installed Western Digital Caviar Black WD5001AALS hard disk drives (500GB, 7200rpm, 32MB buffer, SATA II) and also tried Samsung HD753LJ drives provided by the NAS manufacturer.

The client was a PC with an Intel Core 2 Duo 1.8GHz processor, 4GB of system memory, a Gigabit Ethernet controller on PCIe 1x bus, and 32-bit Microsoft Windows Vista. The NAS was connected to the LAN via a Gigabit Ethernet router. Jumbo Frames technology was enabled on every device that took part in the testing (but certain tests were performed with Jumbo Frames off as indicated in the description of each test). I built a RAID array and created a shared folder on it and used that folder for the tests. The NAS’s other parameters were left at their defaults, so most of the additional services were turned off. These services may have a big effect on the NAS’s real performance (for example, when you are seeding 20 torrents on a fast Internet-connection).

In the first test I compare the performance of the NAS with HDDs from two brands working in five-disk RAID0 and RAID5 arrays. These array types provide the largest storage space. I use firmware version 844.

As you can see, the difference is no bigger than a couple percent. So, there is no point in choosing highest-performance HDDs for such NASes. You should instead choose HDDs basing on such factors as storage capacity, noisiness, heat dissipation and power consumption.

In the second test the NAS is tested with different firmware versions and with Jumbo Frames turned on and off. DSM 2.1 844 and DSM 2.2 914 are used.

The firmware update affects one subtest only: FileCopyToNAS. Jumbo Frames technology has a positive effect on the NAS’s performance in the streamed writing templates.

The third test helps us see the difference between the disk controllers employed in the NAS. To remind you, the fifth HDD and the eSATA port are connected via a SiI3132 whereas the first four HDDs are connected via a 88SX7042 chip. So, I test two single-disk arrays in the first and fifth bays. The other parameters in this and subsequent tests are: firmware 914, Jumbo Frames on, WD disks.

This test shows that the speed of one disk almost does not depend on the disk controller. Marvell’s controller is a mere 2% ahead of Silicon Image’s, despite the more progressive bus.

And now I will test different RAID arrays. The fourth diagram shows the performance of RAID0 which is fast but not fault-tolerant.

When the array grows up from one to two disks, we can see a considerable performance boost. But there are almost no performance benefits when we add even more disks to the array. The maximum read and write speeds are 79MBps and 84MBps in this mode. The DS509+ is somewhat better than the Atom-based NAS we have tested earlier: the QNAP TS-439 had maximum read and write speeds of 76 and 73MBps, respectively.

Well, it is fault-tolerant array types that are more appropriate for this type of NASes. Let’s take a look at the next diagram.

It is clear that the CPU load affects the performance of the RAID5 array at writing. The write speed goes down to 63MBps at high CPU load. In the RAID6 mode the write speed is only 53MBps. The read speed doesn’t change much, though. It still equals the maximum of 78MBps. The Atom N270 working at a considerably higher frequency is slower with its read and write speeds of 74 and 54MBps, respectively.

Surprisingly, the Freescale mpc8533 processor with PPC architecture and 1.06GHz clock rate proves to be faster than the good old x86 at 1.6GHz, even considering the differences in software. Synology’s NAS is very good from this aspect.


The DS509+ from Synology is one of the best SOHO-class Network Attached Storage devices available today. With highest performance and broadest functionality, it is capable of solving a wide range of office and home tasks.

Its five HDD bays allow to build disk volumes up to 10/8TB and you can double this number by connecting an external module. The integrated functionality is impressive. Besides providing networked access to files via all modern protocols, the device can be easily and safely accessed from the Internet. It can feed media files to compatible players, download data and even serve as a video surveillance station.

If this is still not enough, you can extend the number of available services by installing additional modules or use the console-based package management system Optware. The NAS also has a high-quality and robust case and is very quiet for a 5-disk model. So, the only downside of this product is its rather high price which is currently over $850 at Internet shops.

According to the results of our today's test session, we are glad to award Synology DS509+ with our Editor's Choice title as the highest-performance NAS solution: