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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  • UpSpin - Monday, November 14, 2016 - link

    If I understand correctly QNAP offers this:
    Online RAID Level Migration and RAID Capacity Upgrade
  • igot1forya - Monday, November 14, 2016 - link

    I've purchased a couple of these QNAP NAS for work (TS-853A & TS-853U-RP) and interestingly you can upgrade the size of the drives after you max out the RAID. You have to do a single drive swap, then rebuild, then swap the next drive, then rebuild, ect (until all drives are replaced). But it does work! So even if you run out of space (or plan your expansion) you can easily replace all drives in the RAID with larger drives, it just takes a few days to do it smoothly.
  • bJammin - Tuesday, November 15, 2016 - link

    You should be able to do this with Synology too, I believe. Though I haven't done it with mine yet, I remember researching this because I put four disks in mine from the get go, and I wanted to know what to do if I needed more space.

    I love my Synology too, by the way. It's great cause it didn't need any major undertaking to setup, like building a server out of old (or new) hardware and software. I'm not a networking wonderkid, but I know my way around tech toys, and I still think these and other brands are quite viable for those who just want simplicity.

    Mind you, I'm only a home/power user, so I don't need ZFS and FreeNAS and the like. I have physical backups of my important data, and if a movie file stored on my NAS gets corrupted, well dang, I'll just have to replace the file! Gadzooks!
  • jlabelle2 - Tuesday, November 15, 2016 - link

    - You should be able to do this with Synology too, I believe

    Did it. On my Synology DS412+, exactly the same way and worked flawlessly, albeit slowly as it took more than a day for each disk swap to have the rebuilt complete (moving from 2To to 4to drives on 4 bays).

    For info, my father latest DS916+ supports Bfrs out of the box and the latest DSM6.2 (still in beta) is supporting correction of corrupted data (before, it was just detection of those).
  • dave_the_nerd - Monday, November 14, 2016 - link

    Yeah, ZFS doesn't make expanding an array very easy.
  • DanNeely - Monday, November 14, 2016 - link

    Yeah the few times I've seen an explanation on how to do so and asked the opinion of people who knew ZFS well the response I always got was on the line of "well technically it could work but the random IO torture test that it would consist of is likely to kill your drives midway though leaving you with a busted array."

    Dunno where the line between a likely risk and just offending the hyper paranoia that ZFS zealots all seem to have is, but it's been very off putting the times I've looked at it.
  • BugblatterIII - Monday, November 14, 2016 - link

    Synology allows different-sized disks to be added whenever you like. I had 4x2TB disks and later switched out 2 of the disks for 4TB versions (one at a time of course or it wouldn't work).

    Here's a calculator that tells you how much extra space you get for a given configuration:
  • OreoCookie - Monday, November 14, 2016 - link

    Anandtech, this is a great idea for an article, exactly why I come here every day! Thanks!
  • MrCrispy - Monday, November 14, 2016 - link

    There are tons of used SuperMicro servers, 2/3/4U, on eBay. They come with 12-24 hotswap drives, ECC memory, and a cpu much faster than any NAS here. This is commercial grade data center equipment that's so much better than any consumer hardware. You can pick these up for <$400.

    The only disadvantage is the noise and power consumption is not going to be same, but you can replace the power supply/fans, and some people even replace all the internals since the SM cases and backplane is worth it by itself. Install the OS of your choice and get goodies like IPMI etc too.

    This is of course not comparable to a 4bay NAS really but those are too limiting anyway and grossly overpriced. If you just want 4 bays any pc will do.
  • jlabelle2 - Tuesday, November 15, 2016 - link

    - This is of course not comparable to a 4bay NAS really but those are too limiting anyway and grossly overpriced. If you just want 4 bays any pc will do.

    And what would be advantage of the PC? Because a PC is not as small as a NAS, so cannot be put anywhere you want, needs to have a keyboard / screen to administrate. It needs to have a Windows Server licence which is not open to private person.
    And if going to Linux on the PC, you end up with the same kind of issues and questions I asked in page 3 which are that it just does NOT offer the same type of capabilities. It is maybe slighly cheaper (to be seen) but not as powerful or capable.

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