The market for network-attached storage units has expanded significantly over the last few years. The rapid growth in public cloud storage (Dropbox, OneDrive, Google Drive and the like) has tempered the expansion a bit amongst consumers who are not very tech-savvy. However, the benefits provided by a NAS in the local network are undeniable, particularly when complemented with public cloud services. Enterprise users obviously need NAS units with different performance and feature requirements. Our previous NAS reviews have focused more on the performance aspect. With feature set and ease of use becoming important across all market segments, we believe that a qualitative evaluation of the different commercial NAS operating systems is needed to educate consumers on the options available.


Commercial off-the-shelf (COTS) NAS operating systems are popular across a wide range of market segments - business and enterprise users (including those with dedicated IT staff) prefer to have plug-and-play storage units that don't need much babysitting, while the average consumer often wants a media-centric unit without the hassle of re-purposing an old PC or building a file server from scratch. This regularly-updated piece will take a look at the features and usability of the currently popular COTS NAS operating systems.

The following NAS vendors / operating systems are currently covered in this article:

  1. Asustor [ ADM 2.6.5R9N1 ]
  2. Netgear [ ReadyNAS OS 6.6.0 ]
  3. QNAP [ QTS 4.2.2 ]
  4. Synology [ DSM 6.0.2-8451 Update 3 ]
  5. Western Digital [ My Cloud OS 2.21.19 ]
  6. ZyXEL [ FW v5.20(AATB.0) ]

Different vendors cater to different market segments - both in terms of hardware and software features. For example, Asustor, Netgear, QNAP and Synology have units ranging from 2-bay desktop models targeting the average home consumer to 12-bay rackmounts targeting SMBs and SMEs. Western Digital has only desktop units- 1- and 2-bay models targeting entry level users, and multiple 2- and 4-bay models targeting experts, professionals and business users. ZyXEL, on the other hand, focuses on only one market segment - the average home consumer. Every vendor other than ZyXEL in the list above carries both ARM- and x86-based solutions. ZyXEL has only ARM-based solutions in their lineup. The choice between ARM and x86 has to be made by the end-user depending on the requirements (number of users, transcoding support etc.). This piece is not meant to provide inputs on the hardware choice, though we will briefly touch upon how the OS features might vary based on the platform. The hardware currently used to test out the various OS features are tabulated at the end of this section.

Security has turned out to be a very important concern for equipment connected to the network, particularly those exposed to the Internet. Therefore, frequent updates are needed even in the NAS firmwares to handle vulnerabilities that get exposed from time to time. The release date of the latest firmware is also a measure of the commitment of the NAS vendor to their consumers.

Most COTS NAS operating systems are based on Linux, and utilize software RAID (mdadm) with the stable ext4 file system. Recently, btrfs has also become popular in this space. ZFS, due to its resource-hungry nature, has been restricted to units targeting enterprise users. DIY consumers can also get a taste of it using open-source BSD-based operating systems such as FreeNAS.

The following table provides the essential information discussed above in a easy to compare manner.

NAS Operating Systems Evaluation - Comparison Details
Firmware Version ADM 2.6.5R9N1 ReadyNAS OS 6.6.0
Firmware Release Date October 3, 2016 September 29, 2016
OS Kernel Linux 4.1.0 Linux 4.1.30
File System ext4 btrfs (Customized)
Evaluated Hardware 10-bay AS6210T 4-bay ReadyNAS RN214

This piece focuses on the core user-facing aspects of COTS NAS systems. These include the setup process and the quality of the user interface. Storage management and configurable services are the next topic. An overview of user management is followed by discussion of the networking features available in each OS.

Most NAS operating systems have feature parity in terms of core features. However, as we shall see at the end of this piece, there is a difference in ease of use which make some vendors stand out of the crowd. These vendors also try to differentiate with value-added services such as media servers, surveillance (IP camera) support, cloud features and other such features. They will be covered in detail in a follow-on article.

Setup Process and User Interface
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  • driscoll42 - Monday, November 14, 2016 - link

    Any possibility of looking at homebuilt NAS solutions, such as using FreeNAS?
  • Ninhalem - Monday, November 14, 2016 - link

    iX Systems sells COTS FreeNAS systems. I would have liked one of those included here in this comparison.
  • DanNeely - Monday, November 14, 2016 - link

    At $1k for the 4 bay base model iX Systems is operating in a much higher price bracket (ZFS's advanced features devour ram and ECC is strongly recommended so they need much more expensive hardware than the arm/low end intel chips on most of these) than the primarily consumer tier models being looked at here.
  • nagi603 - Monday, November 14, 2016 - link

    You should have titled this article "commercial NAS systems", not "commercial NAS operating systems ". Going by the title, unRAID (a comercial OS that you use on a standard x86 PC) should also be included in this.
  • Threska - Monday, November 14, 2016 - link

    It would be nice if Apple came out with one. The problem across all the one's presented is you have to be a geek just to understand the terminology let alone the concepts. Fine if that's the only group one wants to sell to. It would also be nice when Terra-byte SSDs come down in price to see a small form-factor NAS being built around them. Once again the current crop demands space, and in some cases lots of it.
  • dave_the_nerd - Monday, November 14, 2016 - link

    Apple makes the Time Capsule.
  • MrCrispy - Monday, November 14, 2016 - link

    Apple's solution would be 3x the price, work only with Apple devices, be feature locked and frustrating and require you to upgrade every 2 years, but would work well for a very limited use case.
  • cen - Monday, November 14, 2016 - link

    FreeNAS just wipes the floor with all this crap, it's not even funny. Any so called "tech enthusiast" should be ashamed of buying this off the shelf stuff. And don't even start with the "it's more expensive" card when people are buying top end GPUs like there's no tomorrow. The matter of fact is that ZFS will save you from data corruption, everything else is just a joke.
  • Solidstate89 - Monday, November 14, 2016 - link

    btrfs is designed to offer the same data protections as ZFS. If that's your only reason for using FreeNAS it's a piss poor one.
  • cdillon - Monday, November 14, 2016 - link

    "The same data protections" is not entirely correct. Although btrfs has room to support up to 256 bits of checksum for metadata and quite a bit more than that for the data, it currently uses CRC32C, which is a whole lot better than nothing, but is not great. And it's your only choice.

    The default metadata checksum for ZFS (Fletcher2) is also "not great" but there are others to choose from and you can easily select SHA-256 as the default checksum on any ZFS filesystem, and this is automatically used if you enable deduplication because it requires it. Newer versions of ZFS also offer SHA-512, Skein, and Edon-R, so you have more data-integrity choices that range between ultimate cryptographic security and high performance.

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