Network-Attached Storage Guide

What is a NAS?

Many years ago, I wrote about the importance of backing up your data and covered multiple methods to do so in Windows. One of those was the use of a network-attached storage system, or NAS for short, but they are capable of a lot more than just hosting backups! Modern NAS units come in many shapes and sizes, from budget desktop boxes with just a pair of hard drives to rackmount options with a dozen or more drive bays and high-speed networking.

Just like a PC, you could build a NAS for yourself from parts, but they are more commonly purchased as a base unit and then populated with drives or even bought all together as a package deal.

NAS operating systems, like FreeNAS, HexOS, and Synology DiskStation Manager, are not designed to be used directly with a keyboard, mouse, or monitor. Instead, they are built to be accessed from another computer over the network. Via a web portal, or sometimes a dedicated app, the OS can be used to configure storage options, check drive health, and in some cases run other utilities and hosting services. The exact features available will depend on the OS that is running on the NAS and what other hardware is in the system. Since storage is the focus rather than running demanding applications, NAS boxes generally have lower-end CPUs and limited amounts of RAM.

Although processing power and memory may be limited, the storage options in a NAS tend toward the opposite direction. After all, ‘storage’ is right there in the name! Most NAS units will have between 4 and 12 drive bays, usually for either 3.5” hard drives or 2.5” solid-state drives – though budget models with fewer can be found, and on the high-end (especially rackmount designs), even more may be included. Some brands of NAS can also daisy-chain multiple boxes for bigger arrays, but that is a fairly niche usage and starts to drift into enterprise-class storage instead.

Not only is there room for multiple drives in a NAS, but they also support various methods to provide redundancy – so that if one of the drives were to fail, you won’t lose data. Some do this with basic mirroring, duplicating files on at least two drives, while others use more advanced methods like using parity data. Whatever the approach, providing redundancy will reduce the amount of usable storage space compared to the raw capacity of the drives – so make sure you take that into account when planning!

Another key element of a NAS system, which again is right there in the acronym, is networking. The most basic version of this will be a 1GbE port, which may be fine for some home users, but faster connections and even multiple ports for additional speed and redundancy are also available. I’ll dig into this topic more later on.

NAS at Home

Now that we’ve established what a NAS is, let’s talk about what they are good for. In a home environment, they offer a way to expand storage beyond what laptops and even most desktop PCs have capacity for. This can let you keep more data – whether documents, photos, music, videos, or whatever – without clogging up the drives in your system that may be needed for applications and the project files you are actively working on. As alluded to in the introduction, a NAS is also a fantastic place to back up your whole system to – which is a feature that most modern desktop operating systems support, and can save you a lot of time if you ever need to recover from a local drive failure or botched OS update. This is even more important if you are a freelance photographer or video editor and have client data on your system that may be irreplaceable!

Since the NAS is on your network, it can also let you share files easily between multiple computers without having to go all the way out to a cloud-based storage service. This will usually be much faster and, for those with a lot of data, can save tons of money. For example, 20TB of Google One storage is currently $99.99 a month, or almost $1200 per year. A NAS with 20TB of capacity (after accounting for redundancy) can cost less than $2000, meaning it would pay for itself in under two years – and of course, last many years longer! Selecting the right capacity is important enough that I will dedicate a whole section of this article to that topic.

Some NAS can also run basic services like a Plex media server or even small-scale email or web hosting. Take some time to think through what additional capabilities you might want before making a purchase!

It is also worth noting that hard drives tend to make some noise – they house fast-spinning metal discs, after all – so a NAS with multiple of those constantly running may not be something you want in your bedroom. Planning ahead for where you will put it is important, so here are some factors to consider in that process:

• Physical size and space constraints
• Impact of additional ambient noise
• Location near wired network access and power outlets

NAS for Small Business

A small business is just like a large family, right? I’m kidding, of course, but when it comes to a NAS you can sort of think of it in those terms. In a business environment, more people will likely need to access the shared storage – so you will probably want higher capacity. Likewise, with more people using it, faster networking will be helpful, as long as your network infrastructure isn’t going to be a limiting factor. There can also be a bigger financial impact from data loss, so having more robust redundancy settings that can handle multiple drive failures would be wise. In fact, I would go so far as to say that you don’t want to depend on any single device for storage of important files! Duplicate NAS units in separate physical locations is one approach, or even having a NAS on-site and then backing it up regularly to cloud storage or another off-site repository for an extra level of protection.

You may also have remote employees, whether working from home or traveling, so setting up secure access to your NAS from the wider internet can be important. Almost all NAS have some support for this, but in a professional setting it is critical that this be very safe from outside tampering. If you have an IT department that can help set this up and manage it for you, that is great – but if not, you may want to work with an IT company to help guide you and then be there to provide ongoing support.

Enterprise Storage

When exactly a storage system goes from being a NAS to something more isn’t entirely clear-cut, but for bigger businesses with multiple locations and massive storage requirements, a single NAS isn’t going to be up to the task. That is where software-defined storage comes in.

If a network-attached storage box is like a basic desktop PC, software-defined storage would be like a high-performance workstation or even an HPC cluster. SDS systems are bigger, faster, more robust, and have advanced encryption and monitoring capabilities. They also move from a simple folder structure to various storage protocols across file, block, and object-based frameworks. Procuring and implementing this class of storage solution should definitely involve professional assistance, both to help select the right systems and to get everything up and running properly. Covering it in depth is outside the scope of this article, but we do offer SDS here at Puget Systems – so reach out if you are interested in discussing whether this is right for your company!

Selecting a NAS

If network-attached storage sounds like the right solution for you or your company, the rest of this article is intended to guide you through what to consider when selecting the right NAS system. I hope you find it helpful! If you have any questions or input for other readers, please leave a comment at the end!

Drive Types and Sizes

It is worth noting that fast NVMe drives do show up in some NAS systems as optional cache drives! This can be extremely helpful, particularly for storage systems using slower hard drives, since it can speed up access to frequently used files and help alleviate the bottlenecks that come with multiple users writing data at the same time.

Configuring the Right Type of Drive Array

For the smallest NAS units, with just two drives, there is only one redundancy option: mirroring, or, for systems using classic array terminology, RAID 1. This mode will duplicate all of your content across both drives, so that if either drive fails you still have a complete copy of your data. It does mean that you only have usable space equal to the size of one drive, though!

Once you get into systems with 3 or more drives, pure mirroring becomes a less efficient way to safeguard data. Instead, storage modes that use parity data take over as the go-to options. Single-drive parity, also known as RAID 5, will use up one drive’s capacity and is great for smaller arrays. The more drives you have, though, the higher the risk of a failure – so when exceeding 4 drives it may be wise to step up to two-drive redundancy (RAID 6). As the name suggests, this can protect from up to two simultaneous drive failures – but at the cost of two drives’ worth of capacity.

Picking the Correct Number and Size of Drives

Figuring out the total usable capacity you want, the level of redundancy you feel comfortable with, and the capacity per drive will let you determine how many drives you need:

(Desired Usable Capacity / Capacity Per Drive) + # of Drives Used for Redundancy = Total # of Drives

Alternatively, you can work the other direction. If you know how many drive bays you have available, you can determine what size drives you need to get:

Desired Usable Capacity / (Total # of Drives – # of Drives Used for Redundancy) = Capacity Per Drive

For example, if you wanted to have around 100TB with double redundancy in an 8-bay NAS, that would mean 100TB / (8 – 2 drives) = at least 16.67TB per drive. Obviously that isn’t a real size option, so you’d want to go with 18 or maybe 20TB drives to reach your goal.

Remember that advertised capacity per drive is always a little higher than the true available storage space after formatting, so always round up a little in your calculations!

Networking

Making sure you have sufficient storage space may be the most important factor when configuring a NAS, but ensuring that you can access your data fast enough is not far behind! Part of this comes down to drive speed, as mentioned above, but no matter how fast the drives can read and write, you can be further bottlenecked by your network if you aren’t careful.

Wired network speed is usually measured in bits per second, rather than the bytes that are more common when talking about drive sizes. The ratio there is a factor of eight: 8 bits (small b) = 1 byte (capital B). So if you are looking for, say, 250MB/s of sustained NAS access then you would need 250 x 8 = 2000Mb/s minimum for your network. In reality, you would want more than that to provide some overhead and to account for other network traffic as well.

Common wired Ethernet standards tend to be in multiples of 10, like these popular modes:

• 100Mbps (largely obsolete now)
• 1Gbps (which is effectively 1000Mbps)
• 10Gbps

There are some oddballs in there too, like 2.5Gbps and 5Gbps, which are less widespread – and there are also higher speeds which usually move on from Ethernet to more advanced connections like SFP+. As of this publication, faster network standards tend to be relegated to the realm of enterprise storage, so the focus here will be on getting the right speed and number of Ethernet ports in your NAS – while also making sure that the rest of your network is up to snuff.

Here is a matrix showing network speeds needed to avoid bottlenecking a NAS with various drive configurations:

Drive Type	Drive Quantity	Minimum Recommended Network Speed
Hard Disk Drives (HDDs)	2	2.5Gbps (1Gbps is fine for more casual use)
HDDs	4	5Gbps
HDDs	8	10Gbps
HDDs	12	20Gbps
Solid-State Drives (SSDs)	2	10Gbps
SSDs	4	20Gbps
SSDs	8	25Gbps
SSDs	12	50Gbps

Please note that these estimates are for SATA-type drives and do not factor in having a high-speed NVMe SSD cache – which could allow burst read and write speeds much higher than the underlying storage drives, potentially making even faster networking worth considering.

Some of those speeds can only be accomplished with multiple connections from the NAS to your network. Going that route also provides some level of redundancy in case of a cable or port failure, which is highly recommended for business-class installations. Many higher-end NAS systems offer an expansion slot where you can add the appropriate type of network interface card (NIC) for your installation.

Lastly, keep in mind that it isn’t just the port speed on the NAS itself that matters here! To see these kinds of speeds, your whole network needs to support them. From your router and switches to the client computers and the cables in between, all of your infrastructure must be able to handle your desired speed. If not, anything downstream from the weak point will have reduced performance!

Other Considerations

Beyond the number and type of drives and the right networking, it is also important to think about where the NAS will be located and whether it will impact other aspects of your home or business.