How to Choose a NAS: Capacity, Backup, Apps and Network Speed

Choose a NAS by deciding what it must store, who will use it and how you will recover the data. Then select usable capacity, drive bays, software, memory and network speed around those needs. Include compatible drives, an independent backup and power protection in the plan rather than spending the whole budget on the enclosure.

A phone is full of photographs. A laptop holds the only copy of a business folder. An external drive has become a collection of folders called “final” and “final-new”. These are good reasons to consider network attached storage, but they do not all require the same NAS.

A NAS is a small server that makes storage and supported applications available over a network. It can provide shared folders, backups and photo libraries. It can also add cameras, containers or virtual machines on suitable hardware. The useful starting point is the work, not the largest specification on the product page.

Write Down the Job Before Choosing the Box

Count simultaneous work, not just user accounts. Ten people opening documents create a different demand from ten editors reading media together. Record the busiest task and the devices that run it.

Calculate Usable Capacity and Leave Room to Work

The sum of the drive labels is raw capacity. RAID protection, file-system overhead, snapshots, retained backups and free working space affect how much data you can keep.

Suppose you have 6 TB today and expect to add 2 TB each year for three years. That is 12 TB of primary data. Add a planned 4 TB allowance for retained versions and other working data, giving 16 TB. If you want that to occupy no more than 80% of the planned usable space, the target becomes 16 ÷ 0.8 = 20 TB usable.

Those are planning inputs, not a universal retention formula. A frequently changing design folder may need more version space than a mostly unchanged photo archive. Measure the data you actually have before buying.

Formatting and reserved space reduce what is available, and the operating system may display binary units. Confirm the finished pool rather than treating the table as a final free-space reading. The RAID calculator lets you compare layouts before allowing for your retention and working-space requirements.

Two Bays or Four Bays: Buy the Expansion Route You Need

A two-bay NAS can be an appropriate compact choice when mirrored capacity meets the plan. A four-bay model offers more layout choices and room for a different growth path, but empty bays are not a complete expansion strategy.

Check which RAID changes and drive additions the exact platform supports. Replacing smaller drives can require several rebuilds; adding an expansion enclosure has its own compatibility and failure considerations. Record the supported route before filling the first pool.

Keep drive failure protection separate from backup. RAID can keep a supported array operating through specified drive failures. It does not give you an independent copy when the NAS is stolen, damaged, compromised or incorrectly erased.

Choose the Software You Will Actually Use

Compare the application workflow on Synology DSM, QNAP QTS or QuTS hero, and ASUSTOR ADM. The right question is not which brand has the most applications. It is whether the required application works on the exact model and is comfortable for the people maintaining it.

For photographs, check supported formats, automatic phone backup, access permissions and the recognition tools you need. For business files, check account permissions, version retention and recovery. For scanned documents, separate creating searchable PDFs from indexing and finding them later.

The NAS operating-system comparison focuses on these software choices. The current NAS buying guide provides a separate place to compare current model shortlists.

CPU, Memory and Drives: Check Compatibility First

Ordinary file storage, a photo-recognition job and several virtual machines use resources differently. CPU architecture can determine application support. Memory is shared among the operating system, apps, indexing, backup and any guests you run.

Check installed RAM, supported upgrades and the workload's actual requirements. A large SSD cache also needs appropriate resources; it is not simply a matter of fitting the largest M.2 drives available.

Choose drives from the NAS model's current compatibility guidance and match their workload, endurance and interface to the job. SATA HDD, SATA SSD and NVMe are different devices. An M.2 socket may have model-specific rules for cache, storage pools and supported SSDs.

Synology's compatible M.2 storage-pool support, for example, depends on the NAS and SSD combination. Do not assume every M.2 slot is restricted to cache, or that every NVMe drive can create a supported pool.

Match the Network and the Physical Location

A faster NAS port helps only when the rest of the path can use it. Check the computer's adapter, switch ports, uplink, cabling and whether the client is using WiFi. Local file transfers are a different task from an internet download.

For modest file access, a working existing network may be sufficient. For growing transfers, compare a complete 2.5GbE or 10GbE path. Link aggregation is not an automatic promise that one file copy doubles in speed; the client, protocol and network configuration matter.

Place a tower NAS on a stable, ventilated working surface with room for airflow and cabling. Consider drive noise if the desk is also a recording space or bedroom. Rackmount equipment needs appropriate rack depth, rails where required, cooling and power, not just a spare household cupboard.

The product photo shows the exact enclosure and its drive-bay layout. Use the linked specifications to check the complete configuration rather than ordering from the photograph alone.

Budget for a Complete, Recoverable System

• Enclosure and compatible drives: choose around the required usable space, not just raw terabytes.
• Independent backup: allow for the second destination, retained versions and any cloud or software charges.
• Connectivity: include adapters, switch ports, supported modules and installation where needed.
• Power protection: size the UPS around the load, shutdown support and required response time.
• Setup and handover: accounts, permissions, migration, update settings, restore testing and documentation.

For the storage-media decision, the HDD, SSD and NVMe budget comparison explains where faster storage can earn its cost. Keep the NAS enclosure and the whole system quotation as separate comparisons.

Five Checks Before Moving the Only Copy

1. Open and copy representative files through the intended client connection.
2. Check ordinary, restricted and guest access with separate accounts.
3. Run the backup and restore a deleted file and an older version to a different folder.
4. Confirm alerts, update support and the supported UPS shutdown path.
5. Keep the original source until the migrated files and independent recovery copy have been checked.

The restore-test guide turns a successful job notification into a practical recovery check.

Frequently Asked Questions

Buy the Smallest Complete System That Meets the Plan

For photos, documents and ordinary backup, prioritise usable space, a comfortable application workflow and a separate recovery copy. Add CPU, RAM and faster networking when the identified workload needs them.

A useful buying brief includes today's data, yearly growth, simultaneous tasks, client devices, required apps and the recovery target. With those written down, comparing Synology, QNAP and ASUSTOR becomes a practical decision rather than a contest between specification lists.