The best network-attached storage devices you can buy: Expert tested

ZDNET ranks the Synology DiskStation DS1522+ as the best NAS device currently on the market. This model stands out as a powerful and durable choice, supported by an excellent suite of applications. If the DS1522+ doesn't meet your specific needs, here are the top features to look for in alternative models:

Choosing the right NAS device is a straightforward process, beginning with an assessment of your budget and storage requirements. Vendors typically offer models starting from two bays (allowing for two drives) and upwards.

For those requiring substantial storage, opting for a model with more bays is advisable. However, if you're venturing into NAS devices for the first time, you might want to start with an entry-level or portable option. This allows you to become acquainted with NAS technology without committing to more advanced and costlier equipment immediately.

Below is a simple chart to assist you further in making your decision: 

When in the market for a new NAS device, it's crucial to consider several key factors to ensure you choose the option that best suits your needs:

• Use Cases: Identify the primary function of your NAS device. Whether it's for video editing, setting up a home office, or entertainment purposes, understanding its intended use is vital given the investment. This clarity will guide your decision-making process.

• Budget: Determine your budget early on. NAS systems are significant investments, often carrying a hefty price tag. Additionally, if you opt for a diskless model, remember to account for the cost of purchasing storage separately.

• Bays: The number of bays you need is directly tied to your storage requirements. For those handling extensive multimedia files or planning long-term storage, opting for a device with more bays is advisable.

• Connectivity: NAS devices vary in their connectivity options, from Ethernet and HDMI ports to portable models that can generate Wi-Fi hotspots. Ensure the device you choose has the connectivity features that align with your needs.

Here at ZDNET, our expertise in NAS devices spans decades. Our selections are informed by a combination of in-depth testing, verified customer feedback, and real-world user interactions, with particular emphasis on user-friendly interfaces, performance, a thorough assessment of each model's strengths and weaknesses, and, importantly, price point.

• User-friendly Interface: We prioritize NAS models that are straightforward to set up and manage, featuring software that simplifies usage and enhances sharing and collaboration capabilities.

• Fast Performance: A NAS device accelerates saving and retrieving the data, making it particularly efficient for tasks like video editing—outpacing many cloud storage services.

• Strengths and Weaknesses: Understanding that no model is flawless, we highlight the advantages and drawbacks of each, providing clarity on how they might match your security needs, setup preferences, and workflow requirements, including portability.

• Price: Recognizing budget constraints, we carefully consider each product's price. Although initial costs can be high, they may offer savings over time compared to ongoing cloud service subscriptions.

You can repurpose an old PC or even build a very custom NAS solution to meet your exact needs.

ZDNET author and resident hardware expert David Gewirtz has built his own NAS boxes for years, including some that were highly customized. But as the NAS offerings from vendors like Synology, QNAP, and Drobo improved, the need to build his own diminished. 

If you're comfortable with the prospect of sourcing PC parts and building PCs, you'll probably want to go it on your own. But if you're new to PC building, buying an appliance NAS is probably the way to go. 

RAID, which stands for Redundant Array of Independent Disks, is a data storage technology that combines multiple physical disk drives into a single logical unit for improved performance, redundancy, or both. The primary purpose of RAID is to enhance data protection and improve storage efficiency by distributing data across several disks in various configurations known as RAID levels. 

Here's a breakdown of three of the most common RAID levels:

RAID 0 (Striping)

RAID 0 splits (stripes) data evenly across two or more disks. This configuration offers improved performance because multiple disks can be read or written simultaneously. However, be aware that this provides no redundancy. If one disk fails, all data in the array is lost.

RAID 1 (Mirroring)

RAID 1 duplicates (mirrors) data across two or more disks. This setup offers high data redundancy because each disk in the array contains an exact copy of the data. If one disk fails, the data can be recovered from the other disk(s). However, note that RAID 1 does not improve performance and effectively reduces usable storage capacity by half.

RAID 5 (Striping with Parity)

RAID 5 combines striping with parity, distributing data and parity information across three or more disks. Parity provides fault tolerance, allowing the array to withstand the failure of a single disk without data loss. RAID 5 offers a good balance of performance, redundancy, and storage efficiency.

The primary difference between Network Attached Storage (NAS) and Direct Attached Storage (DAS) lies in how they are connected to and accessed by devices in a network.

NAS devices connect to a network, typically through Ethernet, providing storage that can be accessed by multiple devices on that network. This setup allows multiple users and devices to access and share data simultaneously over the network, making NAS ideal for collaborative environments. NAS units often come with their own operating systems and can support a variety of applications, including file sharing, media streaming, and even server functions like web hosting. These devices are managed via a web-based interface, allowing for remote administration and configuration. Additionally, NAS solutions are generally more scalable, allowing for easy expansion by adding more drives or connecting additional NAS units to the network.

In contrast, DAS devices connect directly to a computer via USB, Thunderbolt, or another direct interface, making them accessible only to that specific computer. DAS systems are typically single-user devices, meaning only the connected computer can access the stored data. For other devices to access this data, it must be shared through the computer to which the DAS is connected. DAS units are simpler and usually do not come with their own operating systems or support for additional applications beyond basic storage. These devices are managed directly through the operating system of the connected computer, without the need for web-based interfaces. Because they connect directly to a computer, DAS devices can offer faster data transfer rates compared to NAS, which relies on network speeds.

The choice between NAS and DAS depends on specific requirements for accessibility, scalability, and performance. NAS is best suited for environments where multiple devices need to access and share data, such as in homes with multiple users, small businesses, or professional settings requiring collaborative access to large files. On the other hand, DAS is ideal for single-user scenarios where fast data transfer rates are critical, such as video editing, graphic design, or personal data storage needs.

Vendors typically estimate the lifespan of a NAS device to be between three to five years. However, it's possible for a NAS to exceed this range, potentially lasting up to a decade. Despite this, the risk of failure escalates over time.

Be on the lookout for signs of hardware deterioration, like sluggish performance and connectivity problems, which may indicate impending failure.

You can potentially improve a NAS device's lifespan by allowing it to hibernate while not in use. For example, if you are away from home for several months, you may want to consider giving it a rest. However, NAS devices can be left on permanently, as many NAS devices have been specifically built to allow this. 

While our top recommendations are above, we also wanted to showcase some other worthy alternatives, including different features, price points, and bay counts.