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NAS Server Explained: Why It’s Cool, and You’d Want a Synology, Too!

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Years ago, somebody asked me about my most important piece of tech and was surprised when I said it was my Synology DS410 NAS server and not the smartphone I was holding.

That was true then. And it’s even more so now.

Additionally, with the benefits of hindsight and real-world usage, I’m also more confident that nobody beats Synology when it comes to NAS servers.

Indeed, I used to have servers from different vendors — WD, QNAP, Netgear, Lacie, Asus, and TerraMaster, to name a few. Now I only keep about a dozen from Synology in my fleet.

If you’re wondering what I’m talking about, this post is for you. And even if you already know about network-attached storage, chances are you’ll learn a thing or two.

I’ll explain in this post, in layman’s terms, NAS in general, and the steps to get a Synology server up and running.

Dong’s note: I originally published this piece on Mar 14, 2018, and did a major update on Aug 2, 2021, to include additional, up-to-date, and relevant information, including that of the latest DSM 7. This is not a sponsored post.

Synology DSD1621 NAS 1
Here’s the best home/SMB NAS server of 2021: The Synology DS1621+.

What’s a NAS server?

NAS is not a name — it would be a terrible one — but an acronym for network-attached storage.

A NAS server is similar to an external drive, but it connects to a router (or a switch) via its network port. And that makes a world of difference.

NAS server vs. external drive

An external drive connects directly to a computer, likely via a USB or Thunderbolt port — it’s a direct-attached storage (DAS) device.

For this reason, a DAS device, like those on this list of top portable drives, works only with one host at a time. Also, it generally just adds additional storage space and not much else.

(Sure, you can attach an external drive to certain routers via a USB port and make the information it stores available to the rest of the network. But that’s just a way to turn your router into a pseudo-NAS server.)

On the other hand, a NAS server is available to the entire network and can deliver much more. You literally connect a NAS server’s network port to your router or switch via a network cable.

Just like most servers, a NAS server can provide many services, such as serving content to streamers, hosting personal cloud storage or a backup destination, working as a mail server, running virtual machines, and a lot more — all at the same time. The possibility is endless.

(OK. Take “endless” with a grain of salt. Different applications require different amounts of resources, and a server, NAS or not, can do only so much at a given time.)

And as for storage, NAS servers can house multiple internal drives to host lots of storage space with redundancy. Among other things, this is the key to the survival of your data.

So to understand a NAS server well, we first need to know RAID. (Already in the know? You can jump to the Synology Hybrid RAID section.)

Redundancy, via the use of RAID, explained

In data storage, redundancy is the use of extra disks (or drives) that are not strictly necessary to provide storage space but to prepare for when a disk fails unexpectedly.

You then have the option to fix that without losing any data or even having to put your system offline.

You get redundancy by using a RAID or a redundant array of independent disks. Different types of RAID deliver different levels of performance and resiliency — the tolerance against drive failures. Still, they all depend on how much storage space you’re willing to put aside for it.

With six drive bays, this little DS620slim offers a wide range of RAID options.

Standard (classic/conventional) RAID setups

As the name suggests, you can lump many disks into a single storage entity with RAID.

Depending on the number of disks in use, you have the following popular standard RAID setups — there are more, but you don’t have to worry about them.


RAID 0 is the only non-redundancy RAID.

Also known as disk-striping, RAID 0 combines two (or more) disks into a single volume.

This volume has the storage space of all involved disks’ combined capacity. For example, if you use two 2TB drives in RAID 0, you’ll get a 4TB volume.

RAID 0 delivers fast performance by writing one copy of data to multiple disks — each disk only needs to hold a portion of the data — and therefore cutting down the amount of writing each disk has to do.

In return, RAID 0 has no data protection. If one of the drives fails, the RAID is dead — you’ll lose data on all disks with no chance of recovering it in full.


Also known as disk-mirroring, RAID 1 is the opposite of RAID 0. It combines two drives into a single volume with the capacity of just one.

Again, if you use two 2TB drives in RAID 1, you’ll still get a 2TB capacity. For this reason, your data survive if one of the two disks fails.

In return, RAID 1’s performance is slow since it has to write a full copy of data to each physical disk — that’s double the amount of writing.


This RAID setup requires three or more drives. It uses one of them as redundancy, so it has the capacity of all involved drives minus one.

For example, if you use three 2TB drives, you’ll get 4TB protected storage space; five will return 8TB, and so on.

RAID 5 delivers capacity, redundancy, and performance but favors speed over resiliency.

In a RAID 5, the more disks you use the faster the performance since the less data the system needs to write to each disk. In a RAID 5 setup, your data is safe when one of the involved drives fails, no matter how many you use.


This RAID setup is similar to RAID 5, but it requires four or more drives and cares more about redundancy by setting aside two drives for data protection. That said, in a RAID 6, your data survives even if two drives fail at the same time.

If you use four drives, RAID 6 is somewhat like RAID 1 mentioned above or RAID 10 below. Ideally, for better performance, you should use at least five disks or more.


This is a standard nested RAID setup, a combination of RAID 1 and RAID 0.

RAID 10 It requires four drives and delivers both performance and data protection. RAID 10 has 100% data safety against one drive failure and a 50% chance against the case when two drives fail simultaneously.

RAID rebuild

When a drive in a redundancy RAID fails, the RAID is now “degraded.” The storage device will give you a notification via indicator lights or beeps. When this happens, you need to replace the failed drive for the RAID to rebuild itself.

The rebuild process can take a long time — hours or even days — depending on the amount of data the RAID stores. But during this time, you can still use the server, just at (slightly) slower overall performance.

A RAID rebuild can be stressful for the rest of the disks in the array. For this reason, it’s a good idea to reduce the loads on your server during this time.

Standard RAID requirements and drawbacks

All standard RAID setups require drives of the same capacity. You can mix drives of different sizes, but all will deliver the same amount of storage as the lowest-capacity one.

For example, if you use 1TB, 2TB, and 3TB drives together, all of them will be regarded as 1TB drives — you have access to a total of just 3TB of raw storage space, and not 6TB.

In other words, when combing drives of mixed capacities, you’ll waste the surplus storage spaces on the higher-capacity drives.

Standard RAID
You waste a lot of storage space when mixing drives of different capacities in a standard RAID.

Also, there’s no way to scale up the storage space in a standard RAID. If you want to increase the RAID’s capacity, you’ll have to follow these steps:

  • Back up the RAID’s data to another device.
  • Rebuild the RAID from scratch with higher capacities drives.
  • Restore the data from the backup.

The whole process is quite time-consuming and requires the server to be taken out of service.

These shortcomings of standard RAIDs are where Synology’s proprietary RAID comes into play.

Synology Hybrid RAID

Besides supporting all classic RAIDs, Synology NAS servers also uniquely feature a proprietary RAID setup called Synology Hybrid RAID (SHR).

SHR is an automated storage management system that, at its core, is similar to standard RAIDs.

For example, when you use two drives, SHR works like RAID 1; with three or more, SHR is now identical to RAID 5, etc. You always have a volume that’s resilient against a single drive failure.

However, SHR has one significant difference: It efficiently supports drives of different capacities. As a result:

  • You won’t waste storage space when mixing drives of various storage sizes.
  • You can conveniently scale up a server’s storage space without having to rebuild the RAID from scratch, by replacing the RAID with larger drives, one by one.
The Synology Hybrid RAID (SHR) allows mixing drives of different capacities without wasting storage space.

By default, SHR always uses one drive for redundancy. However, if you have four drives or more, you can choose to use SHR-2, which reserves two drives for redundancy, similar to RAID 6.

By the way, you can start with SHR and upgrade to SHR-2 later, but you can’t do the opposite.

I’ve used SHR for years and love it. It delivers excellent performance. It’s generally slower than equivalent standard RAIDs but by small margins. However, the combo of the resiliency in data safety and the flexibility in mixed drive support is more than enough to make up for the slight loss in performance.

For example, SHR (not SHR-2) can survive when more than one drive fails simultaneously. That’s almost always the case if you haven’t filled the RAID with more data than the surviving disc(s) can hold.

Still, SHR is only suitable for home or small business applications. If you go super-professional, it might be a better idea to use a standard RAID. That’s the reason enterprise-class Synology NAS servers generally don’t support SHR.

Why Synology is the best NAS choice?

SHR alone makes Synology servers superior to those from other vendors. But this flexible RAID setup is just one of many things that make Synology NAS great.

Sure, Synology is not the only NAS vendor on the market. In the past two decades, I’ve had the opportunity to work with servers from virtually all other vendors.

For basic network storage needs, most, if not all, NAS servers will suffice. Some are also easier to use, and most are certainly more affordable than those from Synology. But if you want to get the most out of network storage, definitely pick a Synology.

While this part might sound like Synology has paid me to write, it didn’t and I didn’t ask. The truth is Synology has been so far ahead in the NAS game that since 2020, I have decided to no longer actively seek to test any other NAS brands because that’d not be a good use of my time. But I’m open to changing my mind.

And that’s true for both home and business users. Let’s start with the naming of its servers.

Synology’s NAS naming convention

Synology NAS servers come in different tiers and models.

Dependent on the number of drives they can house, their hardware specs, and release year, you’ll see names like DS1621+, RS1619xs, FS1018, and so on. It’s a good idea to know what those names mean.

Synology DS1621 NAS Server Front USB
Synology DS1621+: A DiskStation that can hold up to 16 internal drives of the model year 2021 and belongs to the Plus series.

There are three parts in the names, the leading letters, the numbers, and the ending letter(s)/characters. Here’s the breakdown of how to interpret them for home and business models:

The leading letters in a Synology NAS server’s name

This part has two or three letters that show the types of the server:

  • DS stands for DiskStation: A desktop design with drives installed vertically. This type is a popular design for general consumers.
  • DX (DiskStation Expansion): This name is for expansion units that extend the storage capacity of the DS server type.
  • RS (RackStation): A rackmount design server with drives placed horizontally.
  • RX (RackStation Expansion): This one is another expansion unit, but for an RS server.
  • FS (FlashStation): A desktop performance-oriented design built especially for 2.5-inch solid-state drives.
  • NVR (Network Video Recorder): A server designed mostly to work as a video recorder.
  • VS (Visual Station): This server is one dedicated to the Synology Surveillance Station.
  • SA: This series is for scalable enterprise storage solutions and is generally not applicable to home and SMB users.

The number part in a Synology NAS server’s name

This part includes three or four digits to indicate:

  • The last two numbers indicate the release year. For example, 18 means the server is the 2018 model year. (Sometimes, a server is available one year earlier than its intended model year. The DS620slim, for example, came out in 2019.)
  • The digit (s) preceding the model year show the max number of internal drives the server can house, including when used with expansion unit (s). So the DS620slim can host up to six drives.

The ending letters/characters in a Synology NAS server’s name

This part shows the tier a server:

  • XS or XS+: These are top-tier, enterprise-class (and expensive) servers that are the best of the best. These servers are designed to deliver maximum performance and include the most extended warranty with the best support. They are suitable mostly for big businesses that require high availability and uncompromising performance.
  • Plus (+): A high-end server that can do everything a standard server can and much more. It can also host more storage via expansion units. (Note that not all plus servers can do 4K transcoding, which depends on the processor.)
  • (Nothing): This is a standard server. If a server’s name doesn’t end with a letter or character, it’s a server that’s better than J but lower than Plus. It might or might not have 4K transcoding capability. There are two additional flavors of standard server:
    • Play: A standard server with an emphasis on home entertainment. Its hardware prioritizes photos, movies, and music over other functions. A Play server is always capable of 4K transcoding.
    • Slim: A standard compact desktop server that uses 2.5-inch drives.
  • J: This is a lower-tier than a standard server with decent hardware. It’s generally weak in performance and features.
  • SE: An entry-level server with the lowest hardware specs. It’s affordable but suitable only for basic needs. It’s designed to handle a single task at a time.

With that, here’s an example of how to interpret a server’s name: the DS1621+ is a 2021 desktop server that can house up to 16 drives and belongs to the Plus series. The server itself houses only six drives, but it can host two 5-bay expansion units.

Synology servers and storage limits

You might have heard that Synology servers support a limited storage size. Well, that’s true for all servers — there’s none that can handle unlimited storage space.

In the case of Synology, it’s pretty simple. There are three volume size limits, 16TB, 108TB, and 200TB.

Specifically, a server running a 32-bit CPU, including most standard and low-tier servers, has a volume limit of 16TB.

Servers with a 64-bit CPU — that’s most Plus (+) servers and those released in the past five years — can handle 108TB per volume, and most XS and higher-end servers can control 200TB per volume.

Some servers can do larger than 200TB volume size. These are enterprise-class machines with at least 64GB of RAM and run DSM 7.0.1 or later.

It’s important to note that a server can have multiple volumes, so you can always use two or more to double or triple their storage space. Using multiple volumes is not a bad idea since it’d give you more options in backup and replication — you just have to put data in different shared folders.

The box below will give you a list of servers and their supported volume sizes.

Extra: Synology servers and their volume size limits

The list below is based on the information from Synology.

Last updated: Early 2022.

  • 16TB volume limit:
    • 19-series: DS419slim
    • 18-series: DS218j, NVR1218
    • 17-series: RS217
    • 16-series: RS816, DS416, DS416slim, DS416j, DS216, DS216play, DS216j, DS216se, DS116, NVR216
    • 15-series: RS815, DS415play, DS215+, DS215j, DS115, DS115j
    • 14-series: RS814, RS214, DS414, DS414slim, DS414j, DS214+, DS214, DS214play, DS214se, DS114
    • 13-series: DS413, DS413j, DS213+, DS213, DS213j, DS213air
    • 12-series: RS812, RS212, DS212+, DS212, DS212j, DS112+, DS112, DS112j
    • 11-series: RS411, DS411, DS411slim, DS411j, DS211+, DS211, DS211j, DS111
    • 10-series: DS410, DS410j, DS210+, DS210j, DS110+, DS110j
  • 108TB volume limit:
    • 22-series: DS2422+
    • 21-series: RS2821RP+, RS2421RP+, RS2421+, RS1221RP+, RS1221+, DS1821+, DS1621+, DVA3221
    • 20-series: RS820RP+, RS820+, DS1520+, DS920+, DS720+, DS620slim, DS420+, DS420j, DS220+, DS220j, DS120j
    • 19-series: RS1219+, RS819, DS2419+II, DS2419+, DS1819+, DS1019+, DS119j, DVA3219
    • 18-series: RS2818RP+, RS2418RP+, RS2418+, RS818RP+, RS818+, DS1618+, DS918+, DS718+, DS418, DS418play, DS418j, DS218+, DS218, DS218play, DS118
    • 17-series: DS1817+, DS1817, DS1517+, DS1517
    • 16-series: RS2416RP+, RS2416+, DS916+, DS716+II, DS716+, DS416play, DS216+II, DS216+
    • 15-series: RS815RP+, RS815+, DS2415+, DS2015xs, DS1815+, DS1515+, DS1515, DS715, DS415+
    • 14-series: RS2414RP+, RS2414+, RS814RP+, RS814+
    • 13-series: DS2413+, DS1813+, DS1513+, DS713+
    • 12-series: RS3412RPxs, RS3412xs, RS2212RP+, RS2212+, RS812RP+, RS812+, DS3612xs, DS1812+, DS1512+, DS712+, DS412+
    • 11-series: RS3411RPxs, RS3411xs, RS2211RP+, RS2211+, DS3611xs, DS2411+, DS1511+, DS411+II, DS411+
    • 10-series: RS810RP+, RS810+, DS1010+, DS710+
  • 200TB volume limit
    • FS-series: FS6400, FS3600, FS3400, FS3017, FS2500, FS2017, FS1018
    • SA-series: SA3600, SA3400, SA3200D
    • 22-series: DS3622xs+
    • 21-series: RS4021xs+, RS3621xs+, RS3621RPxs, DS1621xs+
    • 19-series: RS1619xs+
    • 18-series: RS3618xs, DS3018xs
    • 17-series: RS18017xs+, RS4017xs+, RS3617RPxs, RS3617xs+, RS3617xs, DS3617xsII, DS3617xs
    • 16-series: RS18016xs+
    • 15-series: RC18015xs+, DS3615xs
    • 14-series: RS3614RPxs, RS3614xs+, RS3614xs
    • 13-series: RS10613xs+, RS3413xs+
  • Over 200TB volume limit (Servers must support Btrfs Peta Volume with a minimum of 64GB of RAM, and run DSM 7.0.1)
    • FS-series: FS6400, FS3600, FS3400, FS2017
    • SA-series: SA3600, SA3400
    • 21-series: RS4021xs+, RS3621xs+, RS3621RPxs
    • 19-series: RS1619xs+
    • 18-series: RS3618xs
    • 17-series: RS18017xs+, RS4017xs+, RS3617xs+, RS3617RPxs

Synology NAS server: State-of-the-art operating system

All Synology NAS servers run a Linux-based operating system, called DiskStation Manager (DSM), of which the latest 7th revision came out in July 2021.

DSM 7 0 Desktop
The Interface of DSM 7.

For this reason, no matter which model you get, you’ll have the same core experience. DSM is where the power of Synology NAS servers lies. It’s by far the most advanced and robust NAS OS.

You access this OS via its web interface — the way you do a router –, but DSM behaves like any other desktop OS within the web page.

It has a start button, a desktop, a taskbar, and a control panel. When working with it, you can open and rearrange multiple windows, log in, log out as different users, etc., all with transitional effects.

In all, working with a Synology NAS server is similar to with a real Windows or Mac computer. DSM is robust and has excellent context-based help and description. If you’re tech-savvy, you can figure things out quite quickly.

Most importantly, DSM is consistent throughout the entire Synology ecosystem. As a result, when you know one Synology server, for the most part, you know them all. Again, it’s just like any Windows or Mac OS.

Synology DSM’s useful core settings and features

Like all OSes, DSM has essential functions, such as user management, network settings, security, shared folders, Time Machine backup support, and many others.

It also has the following, which makes Synology servers so powerful right out of the box:

DSM 7 0 Login Screen
DSM 7’s Login screen with the support for 2-Factor Authentication enabled.
Advanced storage and user management, with 2-Factor Authentication login

Supporting all standard RAID and SHR, a Synology server delivers all the storage setup you’d want, from the most basic to the most advanced levels.

You can also set up storage quotas for each shared folder and conveniently manage permission down to an individual sub-folder.

Starting with DSM 7, all Synology NAS server comes with the option of 2-Factor Authentication login, which you can enforce on individual accounts or a user group.

Once turned on, users can use the phone or an app as a verification key for added security. They can also trust specific devices, making subsequent logins less of a hassle.

DSM 7 Domain LDAP
The support for the Windows Server domain makes any Synology NAS an excellent business server.
Active Directory integration

This powerful business feature allows the NAS server to be part of a network with a Windows Server. Once integrated, you can manage NAS’s resources based on the settings of the domain server.

QuickConnect, VPN, DHCP, Dynamic DNS, DNS and so on

QuickConnect is an easy and quick way to use your server remotely.

All you need to do is register a unique name. After that, you can access your NAS from anywhere, using as the address.

Starting with DSM 7, these features include a free SSL certificate, making remote management a much better experience.

If you don’t want to have an account with Synology, you can skip QuickConnect and use Dynamic DNS. You can also set up the NAS as a VPN, DNS, and DHCP server.

DSM 7 QuickConnect
DSM 7’s QuickConnect feature
Mobile apps

Many Synology NAS applications have their own mobile versions.

That, plus the QuickConnect feature, means you can use your smartphone or tablet to access your server from anywhere.

Examples are content streamings, surveillance apps, photos sharing, download, etc. By itself, you can use DS File mobile app to access shared folders and move data between the server and the mobile device.

Synology DS1621 NAS Server 10Gbps addon
The 10Gbps PCIe add-on adapter for select Synology NAS servers.
Share Folder sync

Sync shared folders in real-time with another Rsync-compatible server — all Synology servers support this — to have another live copy of your data.

Shared Folder Sync works locally and over the Internet via VPN or QuickConnect.

For servers that have two or more network ports, you can combine two ports into a single 2Gbps connection to boost the server’s throughput speed.

Specific servers also have a PCIe add-on slot to host a 10Gbps network adapter or SSD cache.

Package center

That’s an app store where you can install more applications that add features and functionalities to the server.

Synology offers some 100 and counting free, high-quality apps, and you can also manually install apps from third-party developers.

The Package Center is the most powerful feature of a Synology server. It opens up the hardware to endless possibilities.

DSM 7 0 Package Center
The Package Center in DSM 7.

Synology NAS server: Well-thought-out, useful applications

My servers play such an essential role in my daily life because of their apps.

As mentioned above, there are more than 100 official apps. I haven’t had the need (or time) to try them all, but those I’ve used are incredibly useful.

The following are a handful of popular apps, any one of which alone is enough to justify the cost of a server. Again, you can run most, if not all, of these apps and more, at the same time.

Synology Drive

Including a server package and client apps, Synology Drive turns the NAS into a personal cloud server, like Dropbox, but much better.

To use it, you need to install and install the server app from the Package Center. After that, download and install the Synology Drive Client desktop app on your computer. There’s also the DS cloud mobile app for your phone/tablet.

DSM Synology Drive Admin Console
The Synology Drive Admin Console of DSM 7.

With that, you can sync or backup data across multiple (hundreds of) devices in real-time. The way it works, the NAS server will retail a copy of the data and sync that with the clients. You can even choose to use “On-demand Sync” on a client to save its storage space.

This function works within the local network or over the Internet (via QuickConnect mentioned above or a Dynamic DNS connection). There’s no storage limit other than that of the server itself.

You can turn on this feature for all the user accounts on the server, and each account will have its own private sync/backup space. It’s just like having multiple unlimited Dropbox accounts for free.

Imagine always having your data backed up and synced in real-time, no matter where you are, without you having to do anything (other than the initial setup). Once you’ve had that, it’s hard to turn back.

Surveillance Station

You can turn your Synology server into a powerful surveillance system via the Surveillance Station app by adding supported IP cameras.

This app works with a large number of IP cams on the market. Even if a camera is not on the list, as long as it supports ONVIF, you can configure it to work with the Surveillance Station.

Surveillance Station Live V
The Surveillance Station is one of the most-used apps on my Synology NAS server.

Once set up, you can use a browser to keep tabs on your home in real-time or view recorded video based on motion detection. You can also do that via the DS Cam mobile app. For more, check out my full review of the Surveillance Station.

Video Station

This app is one of the many streaming features of a Synology NAS. It automatically organizes movies and TV shows and casts them to the DS Video app, which is available on many platforms, including iOS, Android, Roku, Xbox, Fire Stick, etc.

Again, you can stream content when you’re in the local network or out and about using QuickConnect. Alternatively, Synology NAS also supports Plex and other streaming platforms.

DSM VideoStation
The Video Station is a great way to stream your content to mobile devices.

Keep in mind that, by default, Video Station doesn’t support DTS sound, but you can quickly fix that with a third-party app on the front end, such as VLC.

Download Station

Download Station is the best way to download anything from any source. Download Station will come in very handy if you need to get a large file that takes a long time to download, such as an ISO file of a Linux distro.

You can run many downloads simultaneously and queue an unlimited amount of downloads. And you can also set the max download speed to ensure the server doesn’t hog all the Internet bandwidth and many other settings options.

DSM Download
The Download Station is one of the best download clients.

There’s also a search function that will look among BitTorrent sources for what you want. Double-click on it when you find something, and the download will start.

What’s cool is that you can manage your download remotely via the DS Get mobile app.

Virtual Machine Management

Synology’s VMM is one of the most powerful NAS add-on features.

Available in many servers released in the past ten years, it allows the NAS server to house multiple virtual machines on the inside.

In other words, you can run within the NAS server multiple virtual “computers,” including Windows, Linux, and Virtual DSM, allowing you to operate a whole system in a sandbox for all kinds of advanced applications.

DSM Virtual Machine
The Virtual Machine Manager app of DSM 7

This feature also means you can have an advanced network setup without getting additional hardware. In fact, with the Active Directory integration mentioned above, you can have a Windows Server-based advance network without a separate server.

Snapshot and Replication: The ultimate ransomware protection

Available in all server that supports the new Btrfs file system — most Synology server released in the past decade do — the Snapshot Replication is an excellent add-on security feature.

DSM Snapshot and Replication
You can use Snapshot to retain versions of data regularly.

The Replication portion works somewhat like the folder sync mentioned above and requires additional volume (or storage devices.) It can be a bit redundant.

On the other hand, the Snapshot portion is a must-use. It’s essentially a shadow copy feature that automatically saves a version of the server’s data, by shared folder, on a schedule.

In the case of unwanted data alteration, such as after a ransomware attack, you can restore the data to the previous version, either the entire shared folder or by selecting individual files.

In all, the combo of the 2-step verification for login and Snapshot means you can rely on your Synology server to keep your data safe against malicious changes.

Synology NAS server: Easy hardware setup

All Synology servers released in the past few years share a similar design. Most of them are tool-free, while others only require a standard screwdriver. They come with front-facing drive bays, and you can easily replace/install drives.

Synology DS220 NAS Server 11
It’s easy to install an internal drive onto a Synology drive tray.

As for software, NAS servers are generally not for novice users who want something plug-n-play. That’s also the case with a Synology server. That said, if you’re a tech enthusiast, though, you’ll have no problem figuring one out.

Steps to set up any Synology server

It’s straightforward to set up any Synology NAS box. Here are the common detailed steps.

  1. Mount the internal drives onto the drives trays and insert them into the server. Generally, each tray can house either a 3.5-inch (desktop) or a 2.5-inch (laptop) drive. Former won’t require an adapter, not even screws in newer servers. Synology servers work with all standard SATA drives on the market, including the Seagate IronWolf 110 SSD, or the WD RED SA500. However, it’s a good idea that you use NAS-specific drives.
  2. Connect the server to your router or switch using a network cable and turn it on. By the way, make sure you use one of its built-in LAN ports for this part. An add-on 10Gbps card — as mentioned above — only works after a server’s OS has been installed.
  3. On a connected computer, download, install, and run the Synology Assistant software. The application will detect the server from your network. (Alternatively, in an Internet-connected network, you can open a browser and go to to find the new server that way.)
  4. Pick the detected server and follow the wizard to install the DiskStation Manager (DSM) operating system directly from Synology’s website and finish with the initial setup process.
  5. Log in to the web user interface and customize your server the way you want.

Extra: Step to migrate to a new or different Synology NAS server

Another cool thing about using Synology NAS servers is that you can quickly migrate from one server to another without losing data or system settings. That comes in handy when you need to replace your server due to hardware issues or upgrade to a newer one.

And this process works as a downgrade, too. The only requirement is that the destination server has the same or more drive bays than your existing unit.

And here’s how to do it: physically remove the internal drives from the old server and install them into the new server, preferably in the same order. That’s it!

After that, the first time you turn the new server on, you’ll be prompted to upgrade the OS, like in step #4 above, to the latest version of DSM built for the model. Afterward, all data and most settings of the old server will be present in the new one.

Synology DS1621 vs DS1618 NAS Server Stacked
Upgrading from the DS1618+ to the DS1621+ is as easy as moving the drives from the former to the latter.


There you have it! Now you know why my Synology NAS has been essential for my daily life and why I wouldn’t go with any other brand.

So, no issues? Really?

I can’t find anything purely negative about Synology NAS. In fact, of all servers I’ve used over the years, I had issues with just one, the DS1515+, which died after almost four years of non-stop operation.

However, that turned out to be the fault of Intel’s chip and not Synology. By the way, Synology promptly replaced mine for free, even though it had already been out of warranty.

But just like everything else, these servers are not perfect. Here are a couple of things you should keep in mind before getting a Synology.

  • The cost: Synology servers tend to be more expensive than their counterparts if you compare the hardware specs. The TerraMaster F2 210, for example, has about the same hardware specs as the DS218+ but costs less than half.
  • Expensive upgrades: Synology servers require Synology-approved hardware (RAM, network cards, etc.), which is a lot more expensive than generic hardware from other vendors.
  • Only two IP cameras are allowed out of the box: The Surveillance Station is one of my favorite apps, but each home/SMB Synology server can host just two cameras out of the box. If you want to use more cameras, you’ll have to buy additional licenses at some $60 a pop.
  • Limited support for USB add-on devices: Starting with DSM 7, Synology servers sheds a vast collection of USB dongles. Generally, you can only use a server’s USB ports for storage-related purposes.

So, in the end, the most annoying thing about Synology NAS is the cost. But in this case, you pay for what you get.

The takeaway

I’ve worked on most Synology home and SMB servers, starting with the first servers released more than a decade ago. Since then, I’ve owned more than a dozen, the latest by the time of this post being the DS1621+ — it won’t be my last.

My very first personal server, the DS410, released in 2010, as the name suggests, still works, by the way.

But no matter what Synology NAS you get, you’ll experience most, if not all, of what I previewed above. And rest assured that your server will last. Here’s proof: Synology’s latest NAS OS, the DSM 7.0, supports servers as old as the 2013 model year.

But most importantly, trust me on the significance of a NAS server. Get one from any vendor that fits your budget. At the very least, you’ll have a proper backup solution. And if the server allows for remote access, it’s always better to own your cloud than use one from a third party.

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62 thoughts on “NAS Server Explained: Why It’s Cool, and You’d Want a Synology, Too!”

  1. Dong, you helped me upgrade my Wi-Fi router so now I’m thinking about an NAS. Our needs are pretty basic. We have about 3 tb of family home videos we want to share and send to our TV. We would use it to backup our MacBook Air. And we are thinking of getting an outdoor surveillance camera.

    Here is my question, it seems like the DS220+ would be adequate for what we need. If I got two 8-10 tb drives I would have plenty of room for the videos, backup and surveillance video. Anything I’m missing?

    • What you’re missing, Kent, is why you think you can keep getting free help. How do you deserve it? J/K. Read the post and you can figure it out yourself, it’s all there. And your assessment is fine. 🙂

      • Actually I’ve read this post twice and several more of your Synology posts. You express a preference several times for 4-6 bay systems, I assume that is because that many drives gives you the flexibility to choose whatever RAID fits your needs best. What I’d like to know from someone who has used a Synology NAS and many of the apps is whether a 2 bay system that can only do RAID 1 has any limitations beyond the limitations of RAID 1 itself? Does the OS work better with more than 2 drives? Does Surveillance Station work better with more than 2 drives? For my needs a 2 bay system seems adequate, even with the limitations of RAID 1, but I know almost nothing about Synology NAS and have zero experience with them and I don’t want to find out 6 months later that I should have bought bigger for non-obvious reasons I didn’t know about. Does that make sense? As always I really appreciate your engagement with your readers and your expertise you’re willing to share.

        • Other than the limitation in RAID configurations, as you have noted, Kent, and performance speed (RAID 1 is slow), a dual-bay server is fine. You can get top-capacity HDDs and still have plenty of space.

          But it never hurts to have a server with more bays. You don’t have to use all the bays and can add more dives (and change your RAID configuration) later via SHR. So, 5-bay is the sweet spot. More in this post on how to pick a server. My main server, the DS1821+ has eight bays and I love every single one. 🙂

          I’d take a 4- or 5-bay used server (as long as it can run the latest DSM) over a brand-new 2-bay server.

  2. Hey Dong, love your site. Glad i stumbled onto it.

    Having some weird issues with the scroll bar disappearing and my mouse up/down buttons not scrolliing the page either. Quite annoying. A full page refresh fixes the problem for a few moments. Curious if others are experiencing this issue. Using latest Chrome on latest Windows build.

  3. Hey Dong,
    Good article, I am a Synology fan. I was curious about your explanation of RAID 1. As I understand it, using RAID 1, there is no penalty as you are not writing double the data to the same disk; the data is written twice, but to to separate disks. Data is written to both disks by the controller, however, is is done in parallel, not sequentially. Also, with a proper hardware controller, you may see performance improvements during the read process. Just didn’t want to scare anyone away from RAID 1, it’s perfect for someone using an entry level Synology with 2 bays that is upgrading from an external USB hard drive. Not only do they get the convenience of NAS but also the drive failure protection of RAID.

    • Thanks for the input, JD.

      The system does have to do double the work — or the entire job depending on how you look at it. To make things easier to understand, if you mix two disks of different performances, the system will have to wait for the slower disk to be done with the entire copy of data before continuing — in other RAIDs, only a portion of the data needs to be written on each disk.

      RAID 1 is definitely about data survival and not performance. I didn’t mean to scare folks from any RAID, just wanted to set the expectations straight. And yes, if you have a 2-bay server, RAID 1 is a must – as I explained in the SHR section.

  4. Hi Dong:
    Love your site. Thank you for all the great reviews.
    Question about the NAS servers.
    When I look at a server, say the DS920+, I know it has 5 bays. but I don’t really understand the capacity. I assume the 9 means that it starts with 5 and can add on a 4 bay expansion to get to the 9 in the name. Not sure if that is right. Then I am not sure how much storage it will give me. Do I assume 5 bays at 2TB gives me a total of 10TB of storage with 5TB mirrored? Or could I use 5 drives with 4TB each for a total 20 TB of storage and 10 TB mirrored? Or is it something else? And do the add on expansions follow the same rules?
    It seems simple, but to me it’s confusing.

    • The DS920+ is not a 5-bay, Edgar, it’s a 4-bay, plus the support for a 5-bay expansion unit.

      Generally, each drive bay can handle an internal hard drive of whatever max capacity that is available. If you see a max drive listed in the specs, that means that’s the top capacity of HDDs available at the time of the server’s release. But the server can support subsequent larger HDDs. As for the RAID, check out this portion of the post.

      • Hi Dong,
        Thank you for the great reviews!
        I was thinking about buying Synology NAS, but ended up building one myself.
        Raspberry Pi 4 (8GB RAM) manages software RAID 1 of two HGST 6TB drives in JBOD enclosure. Zero issues in two years. And it survived several hard shutdowns due to electricity problems.
        RPi is connected over Ethernet to RT-AX92U. The router acts as wireless node of XT8 (wired LAN is not an option in some rooms 🙁 ). Both XT8s are using wired backhaul and 42095 FW. Wi-Fi 6 client (Air M1) connected to XT8 node has 40-60MB write and 70-90MB read to/from the NAS.
        Funny part is that using XT8 as wireless node is less reliable than using AX92U.
        My major concern when opting to use software vs hardware RAID is reliability of consumer grade HW RAID controllers.
        Especially when there is additional functionality on top of basic RAID. E.g. in certain cases failure of HW RAID controller may render even RAID 1 disks unusable.

        • Sure, Georgiy. And thanks for sharing your experience. I’d stick with ready-made servers, building a customized NAS is fun but troubleshooting can be daunting. 🙂

          • This is very true. Especially in case of several SATA to USB adapters which might have the same HW IDs in the system :).

  5. Hi Dong,

    Do you happen to have any checklist or recommendation on how to configure the Synology DS1019+ with an ASUS RT-AX89X. I have link aggregation successfully configured on them and it uses the Lan1/Lan2 ports on router and shows as “Bonded” in the DSM. For some reason I am frequently getting a connection failed error on the synology assistant and the router does not seem to be recognized for configuring the port forwarding. Any tips/recommendations?


    • You have to set the same type of LA on both ends, Raghu. And that’s about it. Undo the bond and try again, this time with a bit of attention. Start from the router’s end.

      Also, the disconnection issue might have nothing with the NAS – Router connection. It might be that of the computer you use.

      • I will redo the bonding. Just to confirm, there is just one type of LA – right? On the router, in the LAN –> Switch Control, i just enable Bonding/LA. There is no other option. On the Synology side, i just have to enable LA by creating a Bond in the Network Interface section.

        May be unrelated – but when i try to configure the external access, the RT-AX89X is not listed in the list of routers for automatic configuration. Is that a possible issue?

  6. Hi,

    I use a NAS strictly to share photos between a group of people using a mobile device. So far the only one that works best is WD. Can you tell me if Synology can do this?

    • Yes, totally, Mark. There are many ways for that, too, depending on what you want to do. You can share anything, not just photos. But Synology servers are entirely different from WD, for a good reason. That said, you need to learn how to use them from scratch.

  7. Excellent post. Thank you.

    I cut my NAS teeth on a DS1512+ at work several years ago. I was impressed.

    For home I just purchased a DS620slim, and I appreciate the well-informed and considered post you dedicated to that device, too.

    Keep it up! Thank you!

  8. An excellent article and well written. I am considering the DS1621+ as well, however tossing between this and DS1520+ due to lack of hardware transcoding in the DS1622+ due to the processor. Everything else is a tick for me with that model. Unfortunately no one has mentioned about alternatives against the lack of Plex hardware transcoding support. I am keen to know if you have any suggestions. I’ll be looking to run my 4K media contents on an Apple TV 4K with this NAS, hoping it would work.

    • I don’t use an Apple TV, Sid, but generally this is the best server I’ve used and I so some 4K streaming too.

  9. Hey – I hope y’all are still around monitoring this post’s comments.
    Here’s my questions – We had a ds414j running 3x3TB disks as one SHR volume. The purpose was as the main storage for my wife”s business files, mostly word and excel docs and massive outlook psts.
    It was great. We were able to access files from any of the laptops around our home office as well as her desktop, which was right next to the synology box.
    One month ago the box just flat out failed and suupport said it was a motherboard issue, not power supply. So we got a 420j, popped the disks in, and all was great for about one month. We got degraded volume warnings – it seems one of the three disks fell out of the volume. They advised me to back it up asap so I fired up hyperbackup and synology c2. It just finished. Tomorrow I will also back everything onto a external 4TB drive.
    After reading your article I am wondering if we are using the server best. Should we use Cloud Station, should we check and replace disks if necessary and build a fresh shr volume? Any help would be great.
    I am moderately tech savvy – just enough to screw things up and mostly savvy enough not to lose shit.

    • A couple of things, Richard.

      1. If the volume is not (close to) full, chances are you won’t lose anything, even when more than one drive fails at the same time. But backup is a matter of a daily thing, don’t wait till something is broken to think about it. As a rule, you need to have a backup scheme for a server, as simple as using an external drive connected to the server’s USB port. Backup is different from redundancy.
      2. Hard drives don’t last forever. It’s recommended that you (think of) replacing them every 3 or 5 years, depending on the type you use. But you can check on their status using the DSM’s Storage app. If a drive has a S.M.A.R.T error or bad sectors, it’s time to replace it.
      3. RAID rebuilding is stressful, and the process might push old drives to fail. That said, leave the server alone during this process.
      4. For anything remotely work-related, I’d recommend using Plus server (like the DS1621+) and not J. You can get an older model year or even a used one.

      You’re fine right now (good job on the backup!). Now I’d recommend getting a different server and/or new drives. You’ll have another 3 or five years before you have to think about replacing them. If you get a new server, you can keep the existing server as a backup.

      • You are incredibly nice to answer so quickly. Thank you for that.
        So addressing your comments – here’s the deal.
        We just bought the 420j to be able to smoothly take the 414j hdds and just plug and play. We are not able to purchase a higher-end new NAS at this time so we will be keeping the 420j. That said, it looks like based on your comments and Synology advice we at the very least get new HDD and start fresh.
        My question is – considering the way she uses the NAS, as a daily repository of files she works on – both saving new files and accessing ones she stored there – should we continue operating the NAS as an SHR volume or use the Cloud Station (or similar type options)?
        This whole affair has taught me to have multiple backups of everything – thankfully even though this morning it is now saying there is yet another volume error/failure, files are still accessible AND I was able to copy the files in the volume to C2 backup via hyperbackup. Today I am going to copy everything to a external hdd and then test/repair/etc the existing drives/volumes.
        So – if we go forward setting up a fresh SHR with new hdds on the existing, recently purchased 420j, will I be correct that a safe way to move is to run a full hyperbackup to C2 and set it to run everynight to update files that have changed AND also get her to start saving files also to the external HDD I am adding to our setup?

        • That depends on your data and what you want, Richard. Accessing the server directly means you won’t need to store data on the computer, which is great if you want to share the same data with others in the network or your computer has limited space. On the other hand, using Synology Drive to sync means you always have a backup on your computer (as well as the server). Not sure if the J support it, but generally, using the NAS is a great way to keep your data safe from ransomware/virus via the Backup and Replicator app which shadow-copies your data.

          • “Accessing the server directly means you won’t need to store data on the computer, which is great if you want to share the same data with others in the network or your computer has limited space.” So – yes that’s the case. In choosing this option then I assume using hyperbackup daily to backup to C2 AND a usb external drive would be the safe way to move, yes?
            And thanks again

  10. This is a tremendously helpful article, much thanks. Great to see the concepts, and most of the options and terminology all in one place.

  11. I absolutely love my Synology NAS (DS920+ w/ DX517 filled running SHR-2).

    VMs are fun (even usable) but the real highlight in your article, IMHO, should have been Docker.

    I have containers running stubby+dnsmasq (DNS over TLS), iperf3 (LAN bandwidth benchmarking), librenms (simple LAN inventory and stats), and mariadb.

    Containers have such a silly small footprint and Synology has a full docker CLI stack for diehards.

    I got giddy just typing this lol.

    • Looks like you have exactly the setup I am about to have (DS920+ w/ DX517). I just bought the DX517, because my DS920+ is almost full. My original plan was to expand volumes across the two units and switch from SHR to SHR2, but now I am reading a lot about spanning volumes across two units being a bad idea. There seems to be some logic in this. How have you done it ShellDude and are you happy with your solution?

  12. Hi Dong, I’m very curious why you did not comment on the usefulness of Photo Station / Moments. I’m planning on a Synology and photo management is one main reason. Thanks

  13. What about QNAP? They seem to be the most direct competition for Synology, but pound for pound, QNAPs always seem to have far, far superior hardware and the ability to just generally tinker, which lead me to buy a QNAP over Synology.

    Are there any particular reasons for Synology over QNAP for you? I’m in the process of upgrading and again are assessing the two companies…

    • Stay away from QNAP, Heiko. It tends to offer high-end hardware specs and fancy (largely useless) features, but the OS is bloated and convoluted. Most importantly, it just not reliable. When it comes to NAS server, Synology is FAR ahead in the game. But don’t take my word for it. Get one, use it, then try a Synology, you’ll learn.

  14. I went outside of the Synology family for the first time in over a decade last year (for performance – we do live streaming and ProRes recordings are slow to transfer). Bought a QNAP TVS series… Performance was stellar and having Thunderbolt 3 connectivity was cool, along with 10GBaseT performance. Also love the built in NVMe slots. That said, I now need to get that QNAP up on eBay. It required MUCH more care and feeding than the Synology, and I’m regretting recommending QNAP to one of my clients. Just a lot more headache.

    I have a 5 Bay Synology at home that backs up work files, along with 4 and 5 bay Synologies in 3 other cities at our leads homes to sync files back to us. Back here at the office we use a 7 year old 12 Bay XS series Synology server with a 12 Bay add on chassis. My people also use the ones in their homes for local time machine backups (we synch some of them) as well as as a DVR in places where there’s great OTA TV service like Dallas and LA.

    I admit to feeling frustrated that Synology still doesn’t put 10Gbit on the motherboard and requires add in cards to get NVMe caching nor puts USB-C gen2 onboard, but I hope that the market will pull them that way. (What I’d love to see is a Synology version of the QNAP TBS-453DX to use at events. That thing is awesome)

    But I agree with Dong 100% – having tried other solutions, I’ll take good performance and ease of use/stability all day, every day over rolling my own NAS.


  15. Granted that Synology makes a fair home product, and while the Software and Applications are nice, you can get the same performance (or better in most cases) along with more expandable storage options (if you are willing to invest the time) in a DIY server running ZFS/BTRFS and FreeNAS or Unraid and all of the Apps that Synology has, has an open source counterpart and you are not forced to choose between cache options and networking options. Most available (and realistically priced) generations of enterprise hardware can be had for bargain basement prices (given normal caveats on purchasing from vendors you trust and knowing what you are actually purchasing) on etailers like Ebay. Supermicro chassis and hardware tend to not be saddles with specific proprietary licenses (Unlike HP or Dell Enterprise models) for example and they will support NAS or Enterprise SAS or SATA drives on their backplanes (usually) and they have the added benefit of IPM and many times multiple 10gbt NIC’s ECC RAM etc.

    The added power consumption of course is a factor as is the space necessary to set up a rack (but that can be done in a closet or basement often as not) and of course they are noisy.

    So my question to you paraphrasing Mr. W.C. Fields apocryphal epitaph: All things being equal between a DIY Rackmount with up to 36 Bays and your Synology solutions, which would you choose?

    • I hear you Donald and thanks for the input. I actually was one of those loving DIY NAS servers for many years. They are great if you’re into Linux. But they are all unreliable, at least mine was. They were fun and educational but at some point, I gave up. If you want something that you can just set up once and count on for a long time, go with Synology. Now, you know my answer. 🙂

    • You can’t stop others from attacking your server, Mike. Mine gets thousands of attempts a day and I have done quite a few things to mitigate that. None is successful and that’s what that matters.

  16. Great review! But, no negative about how back in the day thousands of Synology NAS got hacked with Synolocker ransomware. Which at the end of the day exploited a hole thst was Synology’s fault. I’d call that a negative many people lost thousands of files and data. I was one of the smart ones who had unattached backups and didn’t lose anything

    • Hi Mike, I think users are supposed to keep their servers updated. That vulnerability had been patched a long time before it was an issue.

  17. If someone is using a NAS with a 100BT Switch, I encourage them to consider spending $29 to go buy a 1GBit Switch… 😉

    With all the video and backup needs that a NAS will handle, having 10Gbit is fantastic – so multiple users can use full 1Gbit connections.

  18. Compatibility Note:
    According to networking standards, 10GB Eth is only backwards compatible to 1GB Eth.

    Devices with a 10GB Eth plugged into a 10/100 device (switch, PC, etc.) will not work. In order to bridge this gap, you would need to go through a 1GB switch.

  19. Yet another excellent article. Have been lazily delaying finishing my server build on some old hardware and wanting to add a RAID setup, but these honestly seem like they’d be easier to use. If all I want is redundant storage for files like photos, videos etc, no stream of anything, just a place to backup critical files my wife and I don’t want to lose that data, would an SE be perfectly fine or should I spend to get more?

  20. Very interested in this topic. I have several current and 2 older MACs and would love a 5 drive nNAS USING 4 TB SSDs. If the NAS could function as a Time Machine(s) for incremental backups that would be fantastic. But I could live with partitioned weekly or nightly backups. One big issue is encryption of the backups. My understanding is that Apple requires AFSP formatting on SSDs.
    In your discussion of the available apps I did not see mention of a good encryption app.


    • Rob,

      The Synology supports encryption itself for the entire volume which you can turn on or off depending on your needs. That works independently from apps. The Time Machine file format requirement only applies to external drives that plug directly into a MAC, it’s not applicable for a network storage device. For a bit more on Time Machine backup and NAS, you can check out this post.


  21. My big frustration with Synology is that they don’t put 10g on the motherboard. I want both 10g Ethernet and 2x NVMe SSD for cache and I have to choose one or the other via a card. Why can’t both be built in and let me have the card slot for something to expand to rather than just getting me part way to table stakes?

    That said I bought a QNAP and don’t love it, despite its killer value and performance. The software is the Synology superpower even if the hardware is just meh.

    We have 5 Synology Servers, all four bay or more and they are so close to perfect it is incredible. We synch them up via the internet for the photos and videos from projects, as well as synchronizing our time machine backups for offsite backup.

    I buy our ram upgrades from crucial and have never had an issue, fwiw. I buy the 1gb or 2gb lower version NAS and max out the ram with crucial before first boot. So I’m not sure about that negative above.

    I also would love to see an all NVMe NAS from Synology – maybe usb-c powered. Would be an event photographer and videographers dream especially with a 10gbit nic.

    • I hear you, Aaron. But you can’t have everything! 🙂 There are options to have both with Synology right now but you’ll have to pay for their enterprise servers which are a lot more expensive. QNAP is just way behind (or just lost) in terms of software. In a year or two though, you’ll get what you want from Synology.

  22. Thank you for writing this article. It answered all my questions, especially what the model numbers mean. I plan on getting one and going to use everything that you mentioned you use. With heavy use of the ip camera recording.

  23. No doubt it is a well explained review about NAS server but my point here is that why someone prefer nas server on nas appliance. we all know nas appliance is more secure and data security is necessary.

  24. So once I have a camera recording video to the NAS, how do I view the video when I am at a location away from my home network?


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