Compact Network Attached Storage from Synology: DiskStation DS411 Slim

This compact product working with 2.5”hard drives brings low power consumption (“green” solution), quiet operation, reliability and easy disk replacement in a small size. The operating system, Synology DiskStation Manager 3.0, delivers rich features for multimedia, Internet sharing, data protection and energy-saving options. Read more in our review.

by Hugh Barros
02/01/2012 | 10:14 AM

Network attached storage products are generally designed for standard 3.5-inch hard disk drives just because such HDDs offer largest storage capacities and a lowest cost per gigabyte. Considering that SSDs with their high speeds and low capacities are not optimal for NASes, the only possible alternative to 3.5-inch HDDs is their 2.5-inch counterparts. Compared to their bigger cousins, 2.5-inch HDDs have lower capacities and speeds but the same cost per gigabyte, although the latter parameter has been affected by some recent events.


Anyway, what can a 2.5-inch HDD offer to a NAS user? First of all, it consumes less power and produces less heat and noise. And second, it is just smaller! While the first group of advantages can be enjoyed with any NAS, the small size calls for a special compact NAS design. There are but few such models on the market as yet. Two years ago we reviewed Synology’s DS409slim and now we are going to take a look at its successor DS411slim.

Like the 409 model, it has four bays for 2.5-inch HDDs, so the total storage capacity can be quite high (or you can build a fault-tolerant NAS). Another interesting feature is that the DS411slim has an eSATA port along with two USB 2.0 connectors.

Package and Accessories

Synology's product box has become somewhat more eye-catching with pretty colorful pictures against a white background. The downside of the unified packaging is the lack of info about the specific model. You can only see a brief list of its specs, included applications and the contents of the box. The photograph is not large enough to give a clear notion of the exterior design of the product.

Notwithstanding the small dimensions of the NAS itself, its box is rather large at 22.5x22.5x15 centimeters. Besides the NAS, it contains a stand, an external 12V/3A power adapter, an Ethernet cable, some screws, stickers with numbers for the disk bays, a brief installation guide, and a CD with software and documentation. The accessories are in fact the same as those of the previous model and, with the exception of the stand, those of most other modern NASes.

The stand is meant to ensure efficient ventilation because this NAS has a vent grid and cooling fan at the bottom of its case. The software bundle is standard for Synology: DSAssistant (for setting the NAS up in Windows, Mac OS and Linux), Download Replicator (for managing downloads) and Data Replicator 3 (for managing backups). You can also find electronic user manuals and a firmware file on the included CD.

Exterior Design

The DS409slim’s design must have been so successful that the manufacturer hasn't changed anything in its successor. Unfortunately, it means a lot of glossy surfaces that get dirty easily. And they haven't thought about putting a cleaning napkin into the box. The DS411slim is indeed compact at 10.5x14.2x12 centimeters. It is smaller than many dual-disk NASes designed for 3.5-inch disks.

System status, LAN and disk indicators can be seen on the front of the case with one USB 2.0 port below them. Control buttons (Power and Copy) and a couple of LEDs are on a side panel.

You install disks into the DS411slim from the back panel, like into standard hot-swap bays. The disk retention frames are made of plastic to reduce the weight of the NAS and make it smaller. The disk bays lack any locks or latches but, considering the low weight of 2.5-inch HDDs, this design is quite reliable.

The back panel also offers one eSATA port, a second USB connector, a LAN port, a Reset button and a power connector. Everything is exactly like in the previous model. Take note that the USB port is very close to the LAN one, so you won’t be able to plug a thick flash disk in when a LAN cable is connected.

The NAS stands on four tall rubber feet that make it steady on a slippery surface and provide more air for the cooling system. Thus, the exterior design is very good. The DS411slim is beautiful, easy to use and reliable, the only problem being its glossy surfaces.

Hardware Configuration

You don’t have to take the NAS apart to install your disks, but you may want to do so to clean the fan. Unfortunately, the fan is not easy to get to. You'll need a slim and long cross-point screwdriver and the NAS has to be almost completely dismantled in the process. There is a robust metallic chassis under the plastic exterior. The PCBs and the fan frame are all secured on it.

The main PCB has not changed much but its chips have been replaced with more advanced ones. For example, the processor is now a Marvell 88F6282 chip with a clock rate of 1.6 GHz and a small heat-spreader. The system memory has been doubled to 256 megabytes and it’s now DDR3. The flash memory chip is 4 megabytes (it is used to install firmware and boot the OS). Like its predecessor, the DS411slim has a SATA controller Marvell 88SX7042, a LAN chip Marvell 88E1116R and a USB hub GL850G.

The NAS is quite effectively cooled by a 60mm Evercool EC6010L12ER fan. Our HDDs were no hotter than 42°C during our tests. Considering that the fan is located at the bottom of the NAS case and that 2.5-inch HDDs are generally not loud, the NAS turns out to be quiet and can be recommended even for home environments. The fan's operation algorithm can be prioritized for temperature, silence or reduced power consumption. According to the power adapter's label, the NAS doesn't need more than 36 watts of power. The manufacturer specifies a power draw of 16.8 and 9.6 watts when working and idle, respectively. Thus, some of the abovementioned advantages of NASes with 2.5-inch disks are indeed implemented in this model.

Getting Started

Starting the DS411slim up is no different from starting up any other Synology NAS. You put your disks on the plastic frames and insert the frames into the NAS (the disk bays have no locks, by the way). Next you install system software using DSAssistant. The latter utility is available in versions for Windows, Mac OS and Linux, so there should be no compatibility problems.

Besides initializing the NAS, DSAssistant can be used to search for it on the LAN, connect network disks and printers, implement the WoL feature, monitor the NAS's resources and upload photos to it.

A web interface is provided for setting the NAS up. It’s based on modern web technologies and looks like a mini desktop with windows and other pretty-looking features. It is available in multiple languages and supports SSL (you can load your own certificate and change the port numbers).

The new interface may be somewhat confusing for inexperienced users as it offers more freedom than necessary. The older design with a fixed menu tree is usually easier to comprehend. On the other hand, the desktop concept is widespread and shouldn't take long to get used to, especially as there are an integrated help system and a basic setup wizard. Anyway, if you’ve worked with the older type of user interface, you'll have to spend some time learning the new one.

There is a taskbar at the top of the interface window. It has an icon for minimizing windows, a button for opening the main menu of programs, a search field and a notification area. You can have any number of windows open but only for the pages available on the main menu. For example, there can be only one Control Panel irrespective of what page is open in it. However, you can create multiple desktop shortcuts to its internal items.

Besides the administrator, ordinary users can access the NAS’s web interface, too. They will be able to change their password and the desktop’s visual theme and use any of permitted services. Password complexity rules (minimum length, different character sets) can be enforced.

The admin can replace the background picture of the start screen with another picture, change the port numbers or redirect everyone to the protected version of the interface page.

Overall, Synology's web interface is pretty and interesting but not always simple and intuitive.

We used DSM 3.2-1955 for our tests. Synology releases firmware updates for all its NASes simultaneously (the only exception being the models of 2007 which stopped at version 3.1), so the following description can be applied to many other Synology NASes.

Basic Functionality

Disk arrays are set up after choosing the Storage Manager option in the main menu. You can also check out the status of your disks here: product model, storage capacity, firmware version, S.M.A.R.T. information and temperature. S.M.A.R.T. tests can be run manually.

The DS411slim allows using hard disks as JBOD or RAID 0, 1, 10, 5 or 6. A replacement disk can be assigned for fault-tolerant arrays. Synology’s exclusive Hybrid RAID feature can also be selected: it chooses the most reliable configuration based on the number of installed HDDs. HDDs can be scanned for errors when being combined into an array.

You can change the composition and type of your RAID without losing your data. Particularly, you can add more disks into a JBOD, transform single HDDs into a mirror or RAID5, and replace HDDs with larger-capacity ones in a RAID1, 5 or 6.

HDDs can be combined into groups (using RAID technology) and then split up into multiple disk volumes. The capacity of such volumes can be increased without losing data as long as there is free space in the group.

The DS411slim supports iSCSI technology which is usually utilized for virtualized environments. You can build iSCSI volumes as files on existing arrays or enable block access mode for new arrays.

A 2.5GB partition is allotted for the NAS's operating system. The newly installed OS takes about 500 megabytes whereas the remaining 2 gigabytes are for a swap file. There is a copy of the system partition on each disk, so the NAS will keep on working if you remove a disk out of it. The rest of the disk capacity is for user data. The default file system is ext4.

The DS411slim provides access to files via all modern protocols: SMB, AFP, NFS and FTP. Browser-based access and WebDAV are supported, too. When on a Windows network, the NAS can be added to a domain and use the latter’s database of users and user groups. A network recycle bin is available for the SMB protocol. When enabled, a “#recycle” folder appears in the root directory for restoring deleted documents. It cannot be enabled for particular resources but only for all files and folders stored on the NAS.

The AFP and NFS protocols do not have any special settings. You can only enable or disable them and specify a folder for the Time Machine utility in Mac OS X. The FTP server has a dedicated setup page with as many as three tabs. You can change its port numbers, disable unencrypted FTP, limit the number and speed of FTP connections. The FTP server supports passive mode, Unicode filenames and anonymous users (for whom special access rights can be applied).

The easiest access control method for home applications is a local database of users and user groups. But if you’ve got a lot of users, you can utilize a Windows domain or an LDAP server (there is a special software package you can install on the NAS to enable its own LDAP server). When using a local user database, you can prohibit users to change their password and specify a time limit for blocking user accounts. The DS411slim supports quotas for each disk volume.

The home folders service is required for certain functions.

Users can be prohibited to access some of the NAS's services. For example, you can allow a remote user to work with the FTP server but not with the web-based file manager or download station.

A shared folder is the basic network resource. When creating a folder, you can hide it in the network environment, allow it to be indexed by search and media services, enable Windows ACL (to assign access rights to subfolders and individual files on Windows networks). Individual folders can be encrypted. To access an encrypted folder, you have to enter a password or provide a key file (created automatically). The data-transfer speed is going to be lower with such resources. They do not support NFS and have a limitation concerning the maximum size of a file or folder name. FTP and HTTP-based access (including File Station and WebDAV with CalDAV calendars) has additional options that allow to prohibit to view, change or download files. With NFS, you can specify IP addresses, networks or hostnames that have access rights (read only or read & write).

The DS411slim also supports UPnP, Bonjour and SMNP.

The NAS connects to a network via a Gigabit Ethernet interface. It supports manual and automatic IP address setup, Jumbo Frames, IPv6 and DDNS. An integrated PPPoE client is available. A wireless interface can be implemented by plugging in a compatible USB adapter.

There are some features that help you set your DS411slim up for remote access by registering a domain name and setting up port translation on your router. The list of compatible routers includes about 200 models.

As for security features, the DS411slim has an integrated firewall. You can specify individual access rules for each network interface and service. A password guessing attempt can be identified and blocked.

External Devices

The DS411slim supports peripheral devices by means of one eSATA and two USB ports. The USB connectors can be found on the front and back panels of the case. The eSATA interface can only be used for external hard disks. It doesn't support Synology's exclusive multi-disk module. It’s simpler with USB: you can use hubs and have no limits as to the number of external disks.

Such disks can have multiple FAT32, NTFS, ext2, ext3 or ext4 partitions, each represented as a shared folder. The folder's name and access rights can be edited. The NAS will remember such changes and restore them as you reconnect the same disk. You can format the entire disk or a partition as FAT32, ext3 or ext4 in the NAS's web interface. A safe disconnect option is also available there.

Data from a flash disk connected to the front USB port can be quickly copied into a predefined NAS folder by pressing the respective button.

External disks can be shut down when not active. The NAS’s support for USB printers has been considerably expanded. Besides conventional network printing, the DS411slim supports the AirPrint feature for Apple's mobile devices and Google's Cloud Print. Both printing and scanning functions of all-in-ones can be used (but only in Windows). You first install all drivers on your PC and then use DSAssistant to add your all-in-one into your system.

When connected to an uninterruptible power supply, the NAS can monitor the power status via a USB cable and safely shut down according to a selected algorithm: when the battery charge is below certain level, immediately or after a predefined period of time. One UPS can be shared by several NASes via the integrated client-server system.

There is one more application for the NAS's USB ports. You can plug a Wi-Fi adapter into them to link the NAS to your wireless network. The official compatibility list names about 25 adapter models, most of which are 802.11n. The adapter will work as a second network interface without any routing features. If you plan to use the Audio Station feature, it can output audio via a USB-interfaced sound card. Thus, you can play audio on an external sound system right from the NAS.

System Settings

Many of the NAS's services use the integrated clock. It can be set up manually or automatically via the internet.

The interface language is selected automatically, but you can choose it manually as well.

You can separately choose a language for email notifications and encoding for non-Unicode clients.

The NAS can check out for firmware updates and download them for installation after your approval.

You may want to reset the NAS to its factory state, for example to resell it. While doing this, the NAS can delete all data on its disks, or remove all data and configuration information, or reset the MySQL database password. User, group and shared folder settings can be saved and restored.

The DS411slim offers flexible monitoring tools. Besides informational pages that report you its firmware version, network parameters, and the status of its disks and services, there is a module that visually shows CPU, memory and LAN load levels. You can even view the most active OS processes in terms of CPU and memory usage.

The DS411slim has as many as 11 log files. Besides a standard list of system events, you can keep track of users' working with files and backup services. The NAS can report to the admin via email and use SMS for urgent notifications (the latter is a paid service).

The power management options allow to turn internal and external disks off when idle, create a schedule for the NAS work by, and make the NAS turn on automatically after a power failure. The latter option may be useful together with an UPS.

Additional Features

Modern NASes, especially those from the leading brands, offer a number of extra features. Synology is actually one of the leaders in this respect. When enabled, such services appear on the main program menu of the NAS's web interface. Many of them have their own interface available via a special link.

The File Station service can be used for remote access to files. It is a full-featured file manager that works in your browser. It applies access rights, has a special landing page, and can even access your local disks if the browser supports Java. It also features an integrated ZIP archiver, can connect to remote CIFS resources, mount ISO images and play videos (if your browser has a VLC or HTML5 plugin). Its admin version allows viewing Google Docs.

File Station supports mobile browsers, too.

There are two more Stations for accessing content stored on the NAS: Audio and Photo. Audio Station can play audio recordings and online radio via your browser, compatible media player or USB speakers connected directly to the NAS. Client software with the same features is available for iOS and Android. Photo Station helps you organize photo hosting with albums, comments and even blogs. It has a special entry page and user database for higher security. You can upload photos via the web interface, DSAssistant or iOS/Android tools.

Generally speaking, Synology NASes offer broad support for mobile gadgets, which is a serious competitive advantage today.

The DS411slim can host websites using php and MySQL.

As for backup features, the NAS supports rsync and Synology’s own version of this protocol which is supposed to be more efficient. It can also synchronize folders between multiple devices. You can create backup jobs with local folders (including external disks), remote servers and the Amazon S3 cloud service and run them by a schedule. Data encryption and compression are supported. Block access mode is available, too. The additional Time Backup package allows working with multiple file versions.

DLNA and iTunes servers are available for multimedia streaming. The new firmware version allows to choose any folder for indexing. They support all modern multimedia formats and can transcode audio files to reproduce them on any playback device.

The autonomous download system is very easy to use. It supports BitTorrent, HTTP, FTP, Emule, NZB, RSS feeds and two dozen premium accounts for file-sharing sites. It can work by a schedule and offers an integrated torrent search feature. Download jobs can be managed via the NAS’s web interface, the Download Replicator utility or third-party Android tools. You can set up such parameters of the BitTorrent client as connection ports, speed limits, number of connections and seeding options (individually for each download job). The download system is very stable and fast.

If there are IP video cameras on your LAN, the DS411slim can work as a video surveillance system. It supports up to eight cameras but comes with only one license. You’ll have to purchase more licenses for each next camera. The list of compatible products is long, including MPEG4 and H.264, high-res, PTZ and audio-enabled models. Recordings can be made by a schedule or based on a motion sensor. The video surveillance system can be accessed via a separate interface page with a dedicated database of users with different access rights (management or viewing only). You can view the live video and recordings via your browser (browsers other than Internet Explorer are supported, too), a special iOS/Android tool or a separate hardware module with monitor. Multiple monitoring devices can be combined into a single pool for centralized management.

Functionality Enhancements

You can enhance the functionality scope of your DS411slim even further by selecting, downloading and installing ready-made packages from the manufacturer's website using the NAS's interface. There were 10 compatible packages at the time of our writing this. The packages can integrate into the NAS's interface and interact with the NAS as well as other packages. Here are these packages with brief descriptions:

The software packages can be updated without losing their data and configuration. Packages developed by users can be installed, too. You just have to download the installation file and upload it to the NAS via the web interface.

Synology was one of the first NAS makers to officially provide console-based access to its NASes. You can use SSH for secure connection but Telnet should suffice for home applications. It allows you to install additional packages into the OS and change options which are unavailable in the NAS’s web interface. Of course, you should be very careful with this powerful feature.


The DS411slim can accommodate only 2.5-inch HDDs, so we installed Seagate ST9500325AS series disks into it. These Momentus 5400.6 series HDDs have a spindle speed of 5400 RPM, a capacity of 500 gigabytes, a cache buffer of 8 megabytes and SATA 3 Gbit/s interface. The rest of our testbed components were the same as in our earlier NAS tests. We enabled Jumbo Frames and created a disk volume with a shared folder and a user account with full access rights.

Synology has recently updated its firmware to version 1955. One of the important improvements is higher performance of ARM-based NASes. We want to check this out by benchmarking the DS411slim with the previous firmware (version 1922) first.

Notwithstanding its compact size, the DS411slim delivers high performance: an impressive 87 MB/s when reading from the striped array and almost 110 MB/s at writing. The processor turns out to be good enough for working fast with the fault-tolerant RAID5. Checksum calculations lower its performance by 5% at reading and 20% at writing, yet the speed remains high anyway. The performance hit is more serious with the RAID6: up to 10% at reading and 50% at writing. On the other hand, we guess that RAID6 is not a typical usage scenario for this NAS.

Let’s see if firmware 1955 is different.

The performance has indeed improved, especially at writing. The speed of reading is almost the same as before. Anyway, there is no reason not to update. Every publicly available firmware version is very stable and reliable.

You can increase your NAS capacity by connecting external disks. We checked out the speed of such devices using the same Seagate ST9500325AS disk connected via a USB 2.0 adapter or directly via a SATA-eSATA cable (we also used a power cable, of course).

The USB 2.0 interface limits the data-transfer speed. The maximum is 30-40 MB/s, which is much lower than with the internal disks. The eSATA interface is faster.

The ext4 file system makes no difference between the internal disk and the external eSATA one. So, the only problem is that the DS411slim has only one eSATA port.


The Synology DS411slim is a unique NAS. It combines compact dimensions with high performance and broad functionality. It’s a perfect choice if you want a small but functional NAS. And it is surely superior to homemade NAS systems.

Size is the only factor that differentiates the DS411slim from its larger cousins. It features a high-performance platform and functional software. Synology is in fact a leader in terms of NAS software and keeps on improving. When writing this, we learned that the company had already released its beta firmware version 4.0. We’ll discuss it in an upcoming review.

So, if you don’t need a large storage capacity (3.5-inch HDDs can offer 3 terabytes today whereas the largest-capacity 2.5-inch model is only 1 terabyte), the DS411slim can make a good alternative in a small form-factor.

By the way, the compact size doesn't increase the cost of the product. There is no direct counterpart among 3.5-inch NASes, but the DS411slim is cheaper than the DS411 and about as expensive as the DS411j.