Business NAS: How to Choose the Right One and Size It Properly

To choose a business NAS, start from the real workload (file storage, backup, video surveillance or virtual machines), the number of bays you need today and three years from now, the RAID level and disks rated for 24/7 operation. Then weigh up RAM, network ports, data-protection features and, above all, who configures and maintains it over time.

What a Business NAS Actually Is (and Why It Is Not Just a Network Drive)

A NAS (Network Attached Storage) is a storage appliance connected to your network that provides shared disk space for the whole company. In practice it is a small server dedicated to data: centralised folders, per-user and per-department permissions, automated backups and services reachable from several workstations at once.

Do not confuse it with a network USB drive or a one- or two-bay home NAS. A business NAS runs continuously, manages multiple disks in RAID to tolerate failures, offers authentication integrated with your company network and serious data-protection tools: snapshots, replication, versioning and encryption. It is the difference between a shared drawer and a proper archive with a custodian, an access log and a safety copy.

In our field experience with SMEs across Lombardy, the NAS is often the quiet heart of the infrastructure: years of documents, projects, CCTV recordings and, not rarely, the only backup copies all end up on it. Precisely because it holds everything, it deserves the same care as a server when you choose and size it, not a snap purchase based on price-per-terabyte alone.

Start From the Workload: What Do You Really Need It For

Before you read a single spec sheet, there is only one question that matters: what will you use it for. The same appliance that is perfect for sharing files can be completely inadequate for running virtual machines. The most common use cases we come across:

• File storage and sharing: department folders, permissions, access from the office and remotely. This is the baseline use, but it is the foundation everything else is built on.
• Backup target: the NAS as a repository for copies of servers, PCs and cloud services. Here capacity, reliability and the ability to make data immutable are what count.
• Video surveillance: continuous recording of IP camera streams. This demands specific disks and sustained bandwidth, not bursty throughput.
• Virtualisation and services: some NAS units host virtual machines, containers and applications. Here you need CPU, RAM and fast disks, otherwise the project is slow from day one.

Defining the workload already rules out half the market. A NAS built for overnight backup does not need to handle twenty people opening CAD files all day, and vice versa.

The Practical Criteria for Choosing a Business NAS

These are the parameters we assess with clients when it is time to size an appliance. They are listed in order of importance.

1. Bay Count and Capacity (Today and in Three Years)

The number of bays (the slots for the disks) determines both capacity and the level of protection you can achieve. The practical advice: do not size for the space you need today, but for what you will need in three or four years, keeping in mind that part of the capacity is "consumed" by the RAID.

A 4-bay NAS is often the sweet spot for a small business; for setups with video surveillance, many users or virtualisation you move up to 6, 8 bays or more. Watch the usable-capacity maths: with six 8 TB disks you do not have 48 TB available, because a portion is reserved for redundancy. That is the miscalculation that leads to buying an appliance already full after a few months.

2. The Right RAID (Protection, Not Just Space)

RAID is how disks are combined to tolerate failures. It is not a backup, but it is the first line of continuity: if a disk fails, the business does not grind to a halt.

• RAID 1: two mirrored disks, simple and safe for small NAS units.
• RAID 5: tolerates a single disk failure, a good balance of space and protection. On very large disks, though, the rebuild is long and risky.
• RAID 6: tolerates two simultaneous disk failures. On a NAS with high-capacity disks it is the most prudent choice today.
• RAID 10: high performance and reliability, at the cost of more "lost" space.

The choice depends on the number of disks, their size and the level of risk you can accept. We go deeper into this in choosing the correct RAID: it is worth reading before you decide, because the wrong RAID makes you pay at the worst possible moment.

3. The Disks: NAS-Grade, Not Desktop

This is the most common false economy. Fitting desktop disks into a NAS that works around the clock is asking for trouble. Disks designed for NAS (with firmware tuned for continuous operation and for RAID) and, for video surveillance, surveillance disks, are built for different workloads.

A practical rule: do not populate every bay with disks from the exact same production batch, to reduce the risk of simultaneous failures, and always keep at least one spare disk on the shelf. In RAID, the most delicate moment is the rebuild after a failure: if a second disk gives out right then, your data is at risk.

4. CPU and RAM: It Depends What Runs on It

For file sharing alone, modest CPU and RAM are enough. But as soon as encryption, many simultaneous users, virtual machines, containers or the indexing of large volumes come into play, memory becomes the bottleneck. A NAS handling virtualisation with too little RAM is slow and frustrating from day one. Many models let you expand the RAM: always check the maximum limit before you buy.

5. Networking: 1, 2.5 or 10 Gigabit

The network port is often the real performance limit. A single Gigabit port is fine for a small office, but if several people read and write heavy files at the same time, or if the NAS is the backup target for multiple servers, it becomes a squeeze.

Consider appliances with dual ports (for aggregation or redundancy) or with 2.5 and 10 Gigabit when the load demands it. There is little point buying very fast disks and then throttling everything through a single saturated port.

6. Data Protection and Integration

This is where the difference between a consumer NAS and a business-grade one shows. Look for frequent snapshots (to roll back after a mistake or a ransomware hit), replication to a second NAS or to the cloud, volume encryption, granular permission management and integration with your company authentication. These are the features that, on the day of an attack or a human error, make the difference between an inconvenience and a disaster.

A NAS Is Not a Backup: The Most Dangerous Mistake

This has to be said plainly, because it is the misunderstanding that costs the most. RAID is not a backup, and a NAS on its own is not a backup. RAID protects against a single disk failing, not against ransomware encrypting everything, an accidental deletion, a fire or a theft of the appliance.

A serious business NAS belongs in a strategy that follows the 3-2-1 rule: at least three copies of the data, on two different media, one of them off-site (or in the cloud). The NAS can be one of those copies, or the backup target, but never the only line of defence. On this point we work alongside the client to define where the critical data ends up and how it is replicated, often leaning on our cloud services for businesses, which add the external copy to the NAS on site.

The Most Common Mistakes We See in SMEs

Some errors recur with striking regularity:

• Undersizing capacity, forgetting the space consumed by RAID and the growth of the data.
• Fitting desktop disks instead of NAS or surveillance disks, to save a few tens of euros.
• Treating the NAS as the only backup, with no off-site copy.
• Nobody updating the firmware: an exposed, un-patched NAS is a well-known target for ransomware.
• Exposing the NAS directly to the internet with no VPN, open services and weak passwords.

On all of these, sizing carried out together with someone who knows the infrastructure avoids buying twice and discovering the limits at the wrong time.

A NAS Should Be Watched, Not Just Installed

A well-chosen NAS is necessary but not sufficient: it needs to be kept under observation. Disk health, RAID status, remaining space and unusual access attempts all need continuous monitoring. That is exactly why we developed Hector, our AI-based platform that watches over servers, NAS units and network devices, spots anomalies (a disk starting to degrade, a volume nearly full, suspicious behaviour) and flags the problem before it becomes downtime. Because a disk about to fail gives warning in advance, if someone reads the signs in time.

Let's Choose the Right NAS for Your Business Together

Choosing a business NAS is not solved by the lowest price-per-terabyte: it is solved by starting from the real workload, sizing bays, RAID, disks and networking around your work and slotting the appliance into a backup strategy that actually holds up. For more than 25 years we have supported SMEs in Melzo and across Lombardy on servers, storage and data continuity, with the practicality of a team that does the maintenance for real (ISO 9001 and 27001, Google 4.7/5 across 37 reviews).

Call TN Solutions on 02 9517550 for advice on the NAS best suited to your infrastructure, or get in touch through our contact page. We analyse your data and the way you work and tell you, figures in hand, what you need and what you do not.