The number of drive bays is only one part of NAS selection. The NAS needs to match the data, users, network and expected growth.
Practical example: NAS, DAS or SAN?
For shared office files, NAS is often the natural architecture to evaluate first.
Scenario: A 25-user office needs shared departmental files, central backup storage and controlled user access.
A NAS is a natural candidate because it provides file services over the existing network. A directly attached enclosure would tie the storage more closely to one host. A SAN would make more sense where servers require shared block storage, for example in a more complex virtualisation environment.
Decision: For this example, start by evaluating NAS capacity, drive type, network speed, snapshots and backup replication. Do not deploy SAN architecture merely because it sounds more enterprise.
Common mistakes and selection checklist
Common mistakes
- Choosing NAS, DAS or SAN because one architecture sounds more enterprise rather than because it fits the workload.
- Sizing storage only by terabytes and ignoring IOPS, throughput, network speed, snapshots and backup.
- Using one storage system as both primary data and the only backup copy.
What happens if you get it wrong?
Users can experience slow file access or applications can be constrained by the wrong storage path. More importantly, a storage failure or data-loss event can affect both production data and the supposed recovery copy.
Selection checklist
- Decide whether applications need file storage, block storage or storage attached to one host.
- Estimate current usable capacity and realistic growth.
- Identify performance, network and concurrency requirements.
- Check drive type, RAID options, snapshots and expansion.
- Design backup and off-system recovery independently.
A resilient array keeps services available during some drive failures. Separate backups provide recovery from deletion, corruption, malware and site loss.
Determine capacity
Estimate current data, existing backups and expected growth. Remember that usable capacity can be lower than the raw capacity of the installed drives because of RAID or other storage configurations.
Consider drive bays
More bays provide more flexibility for capacity and redundancy. The number of bays should reflect both the current requirement and likely future expansion.
Consider network connectivity
The NAS network interface should match the network environment and workload. A faster NAS interface is most useful when the rest of the network can support it.
Plan resilience
RAID can protect against certain drive failures, but the selected RAID level affects usable capacity and performance. A separate backup strategy is still required.
Think about access
Consider how many users and systems will access the NAS and whether the storage will support file sharing, backups, applications or other workloads.
- Required usable capacity
- Number of drive bays
- Drive type
- RAID and resilience
- Network speed
- Number of users and systems
- Backup requirements
- Future growth
Confirm the exact product specification, supported configuration and compatibility before ordering. Platform generation, firmware, licences and optional components can change what a product supports.