3 For backup and archive data, object storage is usually cheaper than NAS once you look beyond the price of the first purchase. NAS was designed for active, shared file access, and its costs reflect that: controller-based architectures, premium features and refresh cycles that require migrating data. Backup and archive workloads do not need most of those features. They need large capacity at low cost, durability, immutability and the ability to grow for years without disruption, which is what object storage was built for. But the comparison depends on scale, data reduction, licensing models and how long data is kept, so it is worth modeling properly. This article breaks down the cost components of NAS and object storage for backup and archive, explains where each tends to win and shows how to build a fair comparison. For broader context, see our hub on when object storage can replace NAS and storage cost per terabyte. What backup and archive workloads need High capacity that grows steadily, often for years. Sequential writes of large backup files or archive objects. Occasional large reads for restores or retrieval. Durability against drive, node and site failures. Immutability to resist ransomware. Long retention, outliving hardware generations. They rarely need low-latency random I/O, file locking or the advanced data services that differentiate premium NAS. Cost components to compare Raw-to-usable overhead NAS systems typically protect data with RAID, and many organizations replicate NAS to a second system for disaster recovery, doubling capacity. Object storage uses erasure coding, often with lower overhead for the same or better durability, and can distribute data across sites without a full duplicate system. Compare raw capacity required per usable terabyte across the whole design, including the second copy. See erasure coding vs replication. Hardware Object storage commonly runs on standard servers with high-capacity drives, while NAS often uses proprietary controllers and shelves. At large capacities, standard server hardware with dense drives usually lowers cost per terabyte. Software licensing NAS licensing may be bundled with hardware or charged per feature, such as snapshots, replication or WORM. Object storage software may be licensed by capacity or by node. Licensing models matter more as capacity grows, so model them at your five-year capacity, not today’s. Support and maintenance Annual support for NAS platforms often rises in later years, encouraging refresh. Compare support costs across the full period. Refresh and migration NAS refreshes often require migrating all data to a new system every few years, consuming staff time, temporary double capacity and risk. Object storage platforms that support adding new nodes and retiring old ones in place avoid bulk migrations. The scality.com post on object storage hardware refresh explains how. The ARTESCA blog’s analysis of backup storage refresh: expand or replace covers the decision for backup targets. Power, cooling and space Dense object storage nodes with high-capacity drives can store more per rack unit and per watt than many NAS configurations. The ARTESCA blog covers backup storage power and rack costs. Operations Managing several NAS systems, each with its own capacity limits and replication, takes more effort than one scale-out object store. Factor in staff time for capacity management, upgrades and migrations. Backup of the archive Archive data on NAS is often backed up again, consuming backup licenses and capacity. Archive data on object storage can be protected with versioning, replication and object lock, reducing or eliminating separate backups. Ransomware risk NAS backup targets exposed as file shares are vulnerable to ransomware that reaches the network. Object storage with object lock provides immutability that even administrators cannot override. The cost of a failed recovery dwarfs storage savings, so resilience belongs in the comparison. See S3 object lock: immutability and WORM. Data reduction Backup software deduplication and compression reduce stored capacity on either target. Some NAS-based backup appliances include strong deduplication, which changes the comparison for certain workloads. Object storage targets rely on the backup application’s own data reduction. Compare costs using realistic reduction ratios for your data, and be wary of optimistic claims. The ARTESCA blog discusses backup deduplication ratio claims. Where NAS may still compete Small capacities, where the fixed costs of a scale-out object store are not yet offset. Existing NAS with spare capacity, where adding backup data costs little in the short term. Workloads tied to file protocols, where applications cannot write to S3. Where object storage tends to win Large and growing capacities, typically hundreds of terabytes and beyond. Long retention, spanning multiple hardware generations. Immutable backup requirements. Multiple applications sharing one backup and archive platform. Multi-site protection without full duplicate systems. Building a fair comparison Use the same usable capacity and durability target for both options. Model five to seven years, including growth, support increases and at least one refresh. Include the second copy or DR design for each. Include staff time for operations and migrations. Include backup costs for archive data and ransomware protection features. Use realistic data reduction from your own environment. Compare cost per usable terabyte per year, not just purchase price. The framework in total cost of ownership for data storage helps structure the analysis. An illustrative comparison Consider an organization needing 1 PB of usable backup and archive capacity today, growing 30 percent a year, with a second copy for disaster recovery. A NAS design might involve two systems of similar size with RAID protection and replication, a refresh with full migration in year five and separate WORM licensing. An object storage design might use erasure coding across two sites, add nodes as capacity grows and refresh hardware in place, with object lock included. Even without exact prices, the structure shows where savings typically appear: lower raw capacity for the same protection, no duplicate system, no bulk migration and fewer separate licenses. Plug in your own quotes to see the actual difference. Hidden costs on both sides Some costs are easy to miss in a quick comparison. On the NAS side: capacity reserved for snapshots, performance tiers bought for workloads that do not need them, support price increases after the initial term and the project cost of migrations. On the object storage side: network upgrades if backup traffic moves to new paths, initial setup and staff learning time, and minimum cluster sizes that may exceed initial needs at small scale. Including both sets of hidden costs makes the comparison credible to finance teams and avoids surprises after purchase. Restore performance matters too Cost comparisons should not ignore recovery. A cheaper target that restores too slowly can cost far more in downtime during an incident. Test restore speeds for realistic recovery scenarios, such as restoring many virtual machines at once, on each option. Scale-out object storage often delivers high aggregate restore throughput because many nodes serve data in parallel. See the scality.com post on restore speed as the new RTO. Regional considerations In Europe, Japan and the Middle East, data sovereignty requirements often rule out public cloud for backup and archive, making on-premises options the relevant comparison. Energy costs, which vary widely by country, can also shift the comparison, favoring denser, more power-efficient storage. Presenting the case Present results as cost per usable terabyte per year and total five-year cost, with assumptions listed clearly so finance and leadership can challenge and adjust them. Checklist: object storage vs NAS cost Define capacity, growth, retention and durability requirements. Compare raw capacity per usable terabyte, including DR copies. Compare hardware, licensing and support over five to seven years. Include refresh and migration costs. Include power, cooling and rack space. Include operations staff time. Include backup of archives and ransomware protection. Use realistic data reduction ratios. Compare cost per usable terabyte per year. Putting it together For backup and archive, object storage is usually cheaper than NAS at meaningful scale, because it needs less raw capacity for the same protection, runs on standard hardware, grows without forklift upgrades, avoids duplicate DR systems and includes immutability. NAS can remain competitive for small capacities or where spare capacity already exists. Build a fair five-to-seven-year model with your own data, and include resilience, because the cost of a failed restore outweighs any storage savings. Frequently asked questions Is object storage cheaper than NAS? For backup and archive at large scale, usually yes, once overhead, refresh, licensing, operations and DR are included. Why does NAS cost more for archive data? It was built for active file access, with premium controllers and features, and often requires full duplicate systems and bulk migrations at refresh. Does deduplication change the comparison? It can. Compare using realistic reduction ratios from your own data for each option. When does NAS make sense for backup? At small capacities, where spare NAS capacity already exists or where applications require file protocols. How should I compare storage costs fairly? Use the same usable capacity and durability, model five to seven years and compare cost per usable terabyte per year. Further reading See when object storage can replace NAS, moving cold data off NAS filers, storage cost per terabyte, total cost of ownership for data storage and cloud file gateways.
