Which Synology NAS Should I Buy?

This article will answer the question “which Synology NAS should I buy?” to help you figure out what Synology NAS to buy. Synology offers consumers various devices that you can purchase, but picking between them is often an incredibly difficult task. The goal of this article is to give you a baseline that will help determine which NAS device is best for you. We will be focusing on consumer-grade NAS devices in this article. Synology offers small to medium-sized businesses plenty of rack-mounted options, but that won’t be our focus today.

Before we look at the devices, there are a few questions that you need to ask yourself…

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Do I want to use Btrfs?

The first question that you need to ask yourself is if you want to use the Btrfs file system. The Btrfs file system offers a few benefits that Ext4 and other file systems don’t. For this reason, I will not be recommending any devices that don’t support the Btrfs file system.

First, Btrfs is self-healing. To simplify this as easily as I can, data can slowly corrupt over time and you probably wouldn’t even know it until it’s too late. By scheduling data scrubbing schedules and utilizing RAID, the silent data corruption that occurs can be resolved without you lifting a finger. This is incredibly beneficial for all data, but especially helpful for users who would like to store media files on their NAS.

Second, Btrfs gives you the ability to schedule snapshots that will protect your data. Snapshots freeze your data at a point in time and allow you to recover that data if it’s corrupted or lost. This feature gives you the ability to store multiple “versions” of your data on your local device (customized with a specific retention policy) and instantly restore files if needed.

These are the two biggest benefits of Btrfs. If you’re interested in using Btrfs (which is highly suggested), you are limited in NAS selection. Keep this in mind moving forward.

How much storage do I need?

What I’ve learned since purchasing my NAS is that the storage space I thought I needed was significantly less than I actually needed. The reason for this is because I didn’t account for things like Btrfs snapshots and future storage space needs. To give you an idea of how much I was off, I initially calculated my total needs as 12TB of storage. I am currently using over 20TB of storage. Fortunately, I changed my mind and bought a NAS with more drive-bays and larger hard-drives than I initially intended, so I was prepared for it, but it’s hard to express this to someone who hasn’t purchased their NAS yet.

This might sound crazy, but you should probably double the storage space you think you need and purchase a NAS that can hold that total. Especially if you’re going to be using Btrfs since snapshots will take up significantly more space than you think they will.

Which RAID array would I like to use?

Synology offers a few different options, but generally, you will want to use RAID 5, RAID 6, SHR 1, or SHR 2. Both of these options allow either one or two drives to fail without losing any data, with SHR giving the user a little more flexibility. The best thing you can do is use Synology’s RAID calculator to determine the total number of drives you’d need in the size you’d like to use.

Make sure that you also pick the size of the hard drives that you’d like to use.

How many drive bays do I need?

After you determine the estimated total space you’ll need, the RAID array that you’d like to use, along with the hard drive sizes that you’ll be using, you can determine how many drive bay’s you’ll need. If you’d like to prepare for the future (after already doubling your expected storage requirements), feel free to buy a device with an additional drive-bay.

Before we look at the devices, there are certainly differences between them outside of drive-bays. While we are estimating based on storage requirements, there are major differences in CPUs, memory, and expandability. I will do my best to outline those changes below.

Two-bay NAS Devices

Synology DS220+

CPU: Intel Celeron J4025
Memory: 2GB DDR4 non-ECC
Maximum Memory: 6 GB (2GB + 4GB)
M.2 Drive Slots (used for SSD cache): 0
1Gb RJ-45 Port: 2
Warranty: 2 Years

Link to purchase a DS220+

which synology nas buy

Synology DS720+

CPU: Intel Celeron J4125
Memory: 2GB DDR4 non-ECC
Maximum Memory: 6 GB (2GB + 4GB)
M.2 Drive Slots (used for SSD cache): 2 (sold separately)
1Gb RJ-45 Port: 2
Warranty: 3 Years

Link to purchase a DS720+

Editor's Suggestion - Which Synology NAS Should I Buy?

If you truly think that you won’t need more than two-bays, either option is fine, with a slight nod to the DS720+. With that said, if you want redundancy, you’re stuck with RAID 1 or buying an expansion unit (which costs enough to warrant buying a NAS with more drive bay’s up-front). Keep in mind that an expansion unit is only an option with the DS720+.

Four-bay NAS Devices

Synology DS420+

CPU: Intel Celeron J4025
Memory: 2GB DDR4 non-ECC
Maximum Memory: 6 GB (2GB + 4GB)
M.2 Drive Slots (used for SSD cache): 2
1Gb RJ-45 Port: 2
Warranty: 3 Years

Link to purchase DS420+

Synology DS920+

CPU: Intel Celeron J4125
Memory: 4GB DDR4 non-ECC
Maximum Memory: 8 GB (4GB + 4GB)
M.2 Drive Slots (used for SSD cache): 2
1Gb RJ-45 Port: 2

Link to purchase DS920+

Editor's Suggestion - Which Synology NAS Should I Buy?

If your budget allows, the DS920+ is the four-bay NAS you should purchase. The DS420+ comes with a slightly inferior processor and only 2GB of memory. The additional 2GB of memory and better processor warrants the slight increase in price over the DS420+. Another important point to note is that you can expand the DS920+ to nine total drives if you add a DX517 expansion unit.

Five-bay NAS Device

Synology DS1520+

CPU: Intel Celeron J4125
Memory: 8GB DDR4 non-ECC
Maximum Memory: 8 GB (4GB + 4GB) – preinstalled and cannot add more.
M.2 Drive Slots (used for SSD cache): 2
1Gb RJ-45 Port: 4
Warranty: 3 Years

Link to purchase DS1520+

Editor's Comments - Which Synology NAS Should I Buy?

The DS1520+ doesn’t have any competition unless you want to compare it to the DS1019+ that you can buy used. The DS1520+ is basically a DS920+ with 4GB of additional memory and an additional drive-bay. The memory cannot be expanded which is a downside when comparing it to older DS models, but if you didn’t have intentions of doing that, it’s a great option. Before purchasing the DS1520+, I highly suggest checking out the DS1621+ below.

Six-bay NAS Device

Synology DS1621+

CPU: AMD Ryzen V1500B
Memory: 4GB DDR4 ECC
Maximum Memory: 32 GB (16GB x 2)
M.2 Drive Slots (used for SSD cache): 2
1Gb RJ-45 Port: 4
PCIe Expansion: 1 x Gen3 x8 slot (x4 link)
Warranty: 3 Years

Link to purchase DS1621+

Editor's Comments - Which Synology NAS Should I Buy?

We finally have a difference! The Ryzen processor boosts better performance across the board and the DS1621+ supports ECC memory. Not only that, you can upgrade that memory to 32GB if you’d like, which is something that’s not possible for any of the other devices we’ve looked at. The power supply is also contained inside of the device (which is generally higher quality). Overall, the DS1621+ is an actual, practical upgrade from a processor/memory perspective that we haven’t seen yet with the DS220+/720+/420+/920+/1520+. You can also add 10GbE to this device through the PCIe expansion bay, which isn’t possible with the other smaller bay units. If you’re talking purely hardware, this is the “best” one to get, with the “smallest” total drive bays. The only downside is the Intel processor in the cheaper devices will be better for video hardware transcoding. 

Eight-bay NAS Device

Synology DS1821+

CPU: AMD Ryzen V1500B
Memory: 4GB DDR4 ECC
Maximum Memory: 32 GB (16GB x 2)
M.2 Drive Slots (used for SSD cache): 2
1Gb RJ-45 Port: 4
PCIe Expansion: 1 x Gen3 x8 slot (x4 link)
Warranty: 3 Years

Link to purchase DS1821+

Editor's Comments - Which Synology NAS Should I Buy?

The DS1821+ is practically identical to the DS1621+, but comes with two additional drive bays. If you’re in the market for an eight-bay unit, this is the one you want to purchase.

Synology DS1621xs+

I left this for last since it’s overkill for 99% of people who are looking to purchase a consumer NAS. Plus, this falls more into the “prosumer/enthusiast” category, but if you check out any of the tutorials on this site, you might have bigger plans for your NAS so a more powerful device might be desirable.

CPU: Intel Xeon D-1527
Memory: 8GB DDR4 ECC
Maximum Memory: 32 GB (16GB x 2)
M.2 Drive Slots (used for SSD cache): 2
1Gb RJ-45 Port: 2
10GbE RJ-45 Port: 1
PCIe Expansion: 1 x Gen3 x8 slot (x8 link)
5 Year Warranty

Link to purchase DS1621xs+

Editor's Comments - Which Synology NAS Should I Buy?

This is the most “powerful” consumer/prosumer NAS you can purchase in desktop form. The biggest draw is 10GbE support out of the box, but this can be added to either the DS1621+ or DS1821+ models for a reasonable price. Overall, it’s hard to recommend this model, but if you “need to have the best” and don’t want to go with a rack-mounted model, this is the one.

NAS Hard Drive Selection

It’s very important to purchase the correct hard drives for your new NAS. Since NAS devices run 24/7, you need to ensure that you purchase equipment that’s reliable.

If you’re interested in learning which NAS hard drives we recommend, please check out our article on the best NAS hard drives!

Conclusion - Which Synology NAS Should I Buy?

I am hoping that this article helped clarify the question “which Synology NAS should I buy”. These aren’t the only NAS devices that you can purchase. There are other models as well (like a twelve-bay DS2419+) that we aren’t going over since there are very few individuals who will need that type of storage capability.

When you get your NAS, please check out our Synology NAS Setup & Configuration Guide! There are also tons of different tutorials on this site that will help you set up and configure your new NAS!

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