If you're interested in building your own NAS device or even installing a NAS operating system on a pre-built NAS device, you'll eventually have to select an operating system. This is where things tend to get more challenging because you're comparing operating systems that

you potentially haven't used and are trying to determine which option makes the most sense for you. So if you clicked on this video to try and figure out which NAS operating system is best, there isn't a best option for everyone, but there is a best option for you, and

that's what we're going to focus on in this video. Now, if you're coming from a pre-built NAS operating system, these options are drastically different. Generally, pre-built NAS devices come with software that's optimized for the hardware used, but these operating systems are designed to work on a wide

range of hardware. For this reason, one of the most important steps in selecting a NAS operating system is selecting the operating system that you think will function best on the hardware that you're using. This is more important if you're using lower-end hardware, as more

powerful hardware with sufficient resources will most likely work with any of these operating systems. But keep that in mind as you select an operating system. Now, before we get started, there are a few important disclaimers that I want to get out of the way. A NAS is

network attached storage. You can set up a shared folder in Windows that will function as network attached storage, but this video will focus on operating systems that are designed to be used on a NAS. That means that when you load it up, it'll have some sort of GUI to allow

you to create a storage pool and volume, shared folder configurations, and generally have what you'd expect out of a NAS operating system. I'll also focus on official options, so while there are unofficial options that exist, I will not be recommending them. The goal is to

simply highlight some of the biggest differences between these NAS operating systems to help you make an informed decision. Those differences generally revolve around the actual storage pools, as they'll all support shared folders, have their data accessible through file services like SMB, and while one may be

slightly easier or more intuitive than the other from a setup perspective, the end result will be the same. So the first up is going to be the name that you probably heard first, and that's TrueNAS. TrueNAS has two flavors: TrueNAS Core and TrueNAS Scale, which are both free to use.

TrueNAS Core is the successor to FreeNAS, which I believe was released sometime around the mid-2000s, and TrueNAS Scale was released within the past few years. From a NAS perspective, they're designed to function the same. They both run ZFS, which I believe is the best file system

that you can use, as it's designed around data integrity. ZFS is a copy-on-write file system, so it supports snapshots, which freeze your data at a point in time. It also stores data using checksums to detect and correct potential corruption and is extremely scalable. This is the

main selling point to TrueNAS, as it's extremely resilient and is something you can kind of set up and forget from a data integrity perspective. TrueNAS Core and TrueNAS Scale both use ZFS, but there are differences, and it generally comes down to

their underlying operating system, TrueNAS Core, was built on FreeBSD, and TrueNAS Scale is built on Debian Linux. None of that matters for you except to say that it leads to some extreme differences, with one of the biggest potentially being the applications that you plan on

using on the NAS. With prior versions of TrueNAS Scale, Docker was supported, but mainly because it was used as the container runtime for k3s. When k3s switched to containerd, Docker was deprecated in TrueNAS Scale. However, there are still a ton of great applications in

TrueNAS Scale instead of k3s. TrueNAS Core utilizes something called jails and plugins. While they both work well, I think long-term TrueNAS Scale will be a better platform for applications. Next is virtualization, which in my opinion is better on TrueNAS Scale since it uses KVM

while TrueNAS Core uses bhyve. Whether you plan on running virtual machines on the device will depend on your requirements, but the point is they both run virtual machines, though some may have a preference on KVM or bhyve. So up to this point, it

probably sounds like you should use TrueNAS Scale, then, right? Probably, but what TrueNAS Core has is stability and longevity, with all things equal, meaning no hardware compatibility issues. And comparing TrueNAS Core versus TrueNAS Scale as a NAS only, many will still say that TrueNAS Core is

more stable, though TrueNAS Scale has come a long way since its release. The goal of a NAS is to be stable, and stability isn't something you should just dismiss, so that's a huge, huge plus for TrueNAS Core. This naturally leads us to the actual

Hardware requirements for TrueNAS, which are potentially more than you'd expect since TrueNAS runs ZFS, it's a memory-hungry file system. Simply put, the more memory you can use with TrueNAS, the better off you'll be. Personally, I don't think you should

run it with less than 16 GB, but the minimum for both Core and Scale is technically 8 GB. In 2024 though, it's not that crazy of a recommendation to make sure your system has at least 16 GB of memory. There's also the debate of ECC

memory, which is designed to detect and correct single-bit memory errors before writing them to disk. Which is a fancy way of saying that if there's a memory error, ECC memory should fix it before it gets written to disk, where non-ECC memory will technically write that error to disk. How

often this happens is generally what's debated. I'm not going to partake in that debate, but to summarize, there are people who feel you shouldn't ever use ZFS without ECC memory. Then there are people who feel that you should never store data on a NAS without ECC memory, and

the file system being used is irrelevant; you just need to use ECC memory. All of this is to say, you should do your own research on this if you don't plan on using ECC memory because some of those arguments can potentially push you towards a different operating system

with more file system choices. This brings us to ZFS expansion, which will most likely be your biggest problem if you've never used ZFS. With ZFS, you were never able to add a single drive, meaning if you set up a RAID Z1 pool,

with four drives you couldn't add another drive to expand the pool, at least not the way you're probably thinking. Instead, you need to create a second vdev, which, without going too far into detail, the first four drives would be one vdev, and if you needed more storage space

you'd create a second vdev which has to be a mirror of the first vdev. So we have one RAID-Z1 vdev with four drives and the second vdev has to match. So to expand your pool you'd need four drives, not one.

Now, the hope is that at some point a stable version of RAID-Z1 expansion will be available, meaning that you'd select RAID-Z1 or Z2 as an example, and you'd be able to add a single drive and expand the pool. There's been a lot of

development on this from what I've seen, but it's not done yet. And then you'll have to wait for official support in TrueNAS. If you plan on adding your drives at one time and never expanding, this isn't a problem, but if your goal was to

slowly grow the storage space based on your needs, this could be a deal breaker. If this feature is important to you, you can look at the next operating system on our list, which is unRAID. Now, unlike TrueNAS, unRAID is not free. There are different pricing tiers, but you'll have

to work this into your budget if you're interested in it. I really like unRAID and always have in the past. UnRAID versus TrueNAS generally came down to if you wanted to use ZFS. If you did, your only option was TrueNAS. But today, unRAID

officially supports EFS, which naturally makes things more complicated. With that said, if you really want a ZFS pool, you'll probably still lean towards TrueNAS. ZFS on unRAID is still relatively new and it simply functions better than you're used to if you've ever used an on-

RAID array, and if you haven't, you'll probably want a lot of the benefits that historically have pushed people towards unRAID, which a ZFS pool doesn't really support. So why is that? Mainly because when you use an unRAID array, you're not

creating a storage pool, and in fact, you're not actually using RAID as the name kind of implies. You basically create an array that consists of data drives, and this is where your data will be stored. Unlike RAID, where data is striped across disks, unRAID writes that

data directly to the disk. You'll then specify one or more parity drives, which are used for redundancy so that if a drive dies, you don't actually lose your data. When you think of something like RAID 5, you can lose one drive without losing any of your data. With RAID 6,

it's two drives. For unRAID, it functions the same, but you enable redundancy by configuring parity drives as opposed to selecting a specific RAID type. You can configure cache as well, so unRAID functions the same way you'd expect with most other NAS operating systems. It

just does it entirely differently. Now, with unRAID, the drive sizes don't matter, but the parity drives must be at minimum the size of the largest drive in your array. If you need more space, add a drive and keep going. unRAID doesn't require you to actually rebuild a RAID array.

because there isn't a RAID array, which means that you can technically take the hard drives out, put them in a device that supports whatever file system you selected, and view the data. You can do this with RAID as well, but you need to move the entire RAID array, and it has to

basically spin up on the new device the same way as it did on whatever source it was initially running on, meaning the drive order must stay the same, and you have to use the same RAID configuration. With unRAID, pop out a disc, put it in another system, and as long as the new

device can read the file system you selected in unRAID, you'll see the data. If you've never used unRAID, this is probably foreign to you because you're used to multiple drives working together, and technically they kind of do when you take the parity drives into

consideration, but not like they do with a RAID array, which leads us to the point that you're accessing data on the specific drives as opposed to blocks of data across multiple drives, which is what you're doing with RAID. For this reason, you may have drives that are

inactive most of the time because they contain data that you don't access frequently. You don't even have to keep those inactive hard drives spinning with unRAID if you don't want to and can actually put them to sleep if you're not actively pulling data from them. Compare

that to something like ZFS, and the hard drives are constantly working together, so something like that isn't possible. People mainly do this for energy saving purposes, as there's a pretty big debate on if sleeping hard drives do or do not extend the life of the drive, but a hard

drive that's not spinning does save power. The point is all of this functions entirely differently than it does with something like ZFS, and you can't really do any of what we just discussed with ZFS, which is why this topic is arguably the biggest reason why you would or

wouldn't select unRAID over ZFS. This all leads us to the biggest downside of how unRAID works, and it's hard drive performance. Since data is stored on individual drives, you're generally limited to the overall read/write performance of that individual drive. With RAID, multiple drives work together

and for that reason, you're not limited to the performance of one drive the way you are with unRAID. Instead, the total number of drives work together based on the RAID type you're using, and the performance of that RAID pool is faster. For this reason, you really should use a

cache pool with unRAID, as it will drastically improve the overall write performance. With cache, when you're writing data to the array, it first gets written to the cache pool, which will generally consist of SSDs, and later gets moved to the array. This gives you

drastically faster write performance than you'd get if you didn't have cache. But the biggest downside is that unRAID unfortunately doesn't have the best read performance, and you're generally limited to the speed of the drive that you're pulling data from. This could be a deal

breaker for you, or could force you to use SSDs as opposed to HDDs for faster read performance. If you care solely about flexibility right now, unRAID is probably the better choice, as long as you understand the potential downsides. unRAID offers all of the usual

applications, Docker containers and VM support that you'd expect and is extremely comparable to TrueNAS scale in that regard. So I wouldn't necessarily pick one over the other for third-party tools, but injecting my subjective opinion into things, UnRAID does seem a little bit easier to use when it comes

to applications. For all of these reasons, your decision to use UnRAID should generally come down to flexibility and performance. With our next NAS operating system, OpenMediaVault, being a good option for total beginners or people coming from a pre-built NAS operating system that aren't ready to use TrueNAS or

UnRAID just yet, OpenMediaVault is really just a somewhat user-friendly free NAS operating system. I say somewhat because some things are super easy to do and others are flat-out convoluted. It's built on Debian Linux, supports all of the RAID types you'd come to expect and has

support for a bunch of different file systems, though most will probably use BTRFS for the snapshot functionality. OpenMediaVault technically supports ZFS as well, though it's handled through a third-party plugin and using OMV Extras, which is a separate install. But if you're using OpenMediaVault, you'll

probably install OMV Extras anyway with the ZFS plugin. I don't think it's technically official support, but it's developed in conjunction with the core of OpenMediaVault, whatever that means. With the help of OMV Extras, you'll have support for Docker, KVM for virtual

machines, VPNs like WireGuard and more. In my opinion, if you're planning on using OpenMediaVault, OMV Extras is a required install. Without OMV Extras, I'd say that OpenMediaVault is a fairly basic NAS operating system and I

probably wouldn't go out of my way to install it, but with OMV extras installed, it's a competitor in this space. All of this leads us to recommendations for you and whatever NAS device you're building. We'll start with Open Media Vault. The biggest downside

with Open Media Vault is that it's going up against TrueNAS and unRAID. As it stands, Open Media Vault is a lightweight NAS operating system that you can even install on a Raspberry Pi, but are you going to install it on a rack-mount NAS

device? Probably not. Are you going to install it on a desktop NAS device? Probably not. If I'm being honest, I've had trouble thinking of why, because it's not bad, it's just not that great either. I've seen it mostly used in the context of Raspberry Pi devices, and in that

space, it's a really great option. It's just hard when comparing it to TrueNAS and unRAID. And comparing TrueNAS and unRAID isn't particularly easy either. It's just easier to say that both options are most likely better than Open Media Vault.

Outside of extremely specific hardware that could push you towards OMV for that reason, selecting a NAS operating system ultimately comes down to the question that it's always come down to: Do you want to use ZFS? And will you have the recommended system resources for it? If

you do, you can use TrueNAS Core, Scale, or even unRAID, but I'd probably lean towards TrueNAS, as TrueNAS is designed to run ZFS and that's it. You'll have to compare and contrast the differences between TrueNAS Core and TrueNAS Scale to

determine which is best for you, but in my opinion, I'd probably lean to the side of TrueNAS Scale as it just seems like iXsystems, who creates TrueNAS, is pushing it harder, and TrueNAS Core seems to be in a long-term support phase with that.

That said, long-term support isn't bad, and for some people, they might actually prefer that since TrueNAS Core is free. It's been around for close to 20 years at this point and has supported ZFS for close to 15 years. So if stability is

important, TrueNAS Core is a great option and probably a better option than TrueNAS Scale. You may have some hardware compatibility issues with TrueNAS Core, and if you do, that's where TrueNAS Scale will shine, but you'll have to determine that when you install it. Now, if flexibility or future

expansion is important and you don't want to jump through the potential hoops that ZFS has in that regard, UnRAID is awesome if you've amassed a bunch of hard drives that are just laying around and you want to create an array with them. You probably won't be able to pick

a better NAS operating system than UnRAID. UnRAID comes with the downsides we already discussed in terms of read performance, but write performance can be improved with an SSD cache pool. TrueNAS and Open Media Vault won't handle mixed-size drives like UnRAID does, so if

you actually want to utilize them without creating multiple pools, UnRAID is going to be your best bet. UnRAID also has a loyal and strong community where you'll get great support, which is important for any operating system. Ultimately, you need to assess your hardware and try and determine which is

best for you for you when you remove pre-built NAS operating systems from the equation, these are the three most common NAS operating systems you'll come across and they all function similarly but differently. So I hope that some of this information helped determine which

option is best for you. If you made it this far, thank you for watching. I'll see you guys next time.

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