Glossary
Object storage vs. NAS
Object storage vs. NAS is the choice between a flat pool reached over an HTTP API, where whole objects are written and read by key, and a shared file system mounted over the network, where programs edit inside files and use locks. The access pattern of the data decides which one fits.
Where do the two differ most?
| NAS | Object storage | |
|---|---|---|
| Access | Mounted share with folders | HTTP API, objects by key |
| Writes | In the middle of a file, with locks | Whole object replaced, last write wins |
| Namespace | Folder tree, bounded by the file system | Flat buckets, grows by adding nodes |
| Strong at | Shared editing, home directories | Billions of items, multi-site, immutability |
NAS lets programs write into the middle of a file, and locks coordinate several users. Object storage speaks S3 over HTTP, and every write replaces the whole object. Object storage is the one that gets bigger without a ceiling.
What decides it?
The deciding fact is the access pattern, not the amount of data. If applications edit files in place or depend on file locks, NAS is the right shape. If data is written once and read often, held in billions of items, spread across sites, or has to be immutable, object storage fits. Cost follows from that: object capacity is cheaper at scale, while NAS earns its price where it removes work from users and applications.
What is the mistake teams make?
The common error is mounting object storage as a file system so applications that edit in place keep working. Tools that present S3 buckets as folders hide the whole-object rule, and every small edit then rewrites an entire object. Renames and listings are slow, because a folder rename means copying everything under a prefix. The application runs, but badly. A related approach is a platform that serves both protocols, covered under multi-protocol storage.
Do the two coexist?
Most estates run both: NAS for active work, object for backup, archive and AI data. Cold files that have not been touched in months move from NAS to object, which frees the filer and its backup window. The extra tiering step is a policy decision, not an application change.
The cost of getting it wrong is migration. Data placed on the wrong side often runs for a year or two before the access pattern shows up as slow renames, a backup window that never closes or applications that fail on partial writes. Moving it later means copying every item and re-pointing every consumer.
Immutability is a further dividing line. Object storage can lock an object against change or deletion until a retention date, enforced by the storage itself. A file share can offer snapshots and read-only flags, but in-place writes and administrator rights mean the lock is only as strong as the accounts that can undo it.
Frequently asked questions
Can an S3 bucket replace a file share?
Only for data that is written once and read many times. A share used for editing needs in-place writes and locking, which S3 does not offer.
Which is cheaper per terabyte?
Object storage is usually cheaper at scale because it grows on standard servers. A fair comparison counts the backup, migration and administration costs of each.
What about performance?
NAS tends to give lower latency on small files. Object storage gives high aggregate throughput across many parallel clients.
Related terms
- Network-attached storage: the shared file system side.
- Object storage: the flat pool side.
- Multi-protocol storage: one copy over file and S3.
- NAS consolidation: moving filers onto fewer systems.
- Storage tiering: moving cold data to cheaper storage.