NAS vs SAN: What's the difference?
NAS provides file-level storage over a network, while SAN provides block-level storage to servers through a dedicated storage fabric or IP network.
NAS
Network Attached Storage exposes shared files through protocols such as SMB or NFS.
SAN
A Storage Area Network presents block devices or LUNs to servers, commonly through Fibre Channel or iSCSI.
Key differences between NAS and SAN
| Decision factor | NAS | SAN |
|---|---|---|
| Access model | File-level access using protocols such as SMB or NFS. | Block-level storage presented to servers as disks or LUNs. |
| Typical clients | Users, applications and servers access shared file paths. | Servers and virtualization hosts mount block devices and create filesystems on them. |
| Operational complexity | Often simpler for general file sharing and departmental storage. | Usually requires more specialized storage networking, zoning, multipathing |
Choose NAS if
Choose NAS for shared files, user data, simple application storage or straightforward network file services.
Choose SAN if
Choose SAN when servers or virtualization platforms need centralized block storage with specific performance and availability requirements.
Practical example
A design team stores shared documents on an SMB NAS so Windows clients can open files directly. A virtualization cluster uses a SAN LUN over Fibre Channel or iSCSI as shared block storage for virtual-machine datastores. Both are centralized storage, but the hosts interact with them differently.
Can you use NAS and SAN together?
Organizations often run both: NAS for user and application file shares, SAN for virtualization or database workloads that need centralized block storage. Some storage appliances can provide both file and block protocols from the same platform, but the access model still differs.
Common mistake to avoid
Do not choose SAN simply because it sounds more “enterprise.” File workloads can be simpler and safer on NAS, while block storage requires the host filesystem or cluster layer to coordinate access correctly. Match the storage protocol to application behavior and operational skills.
Key takeaway
NAS and SAN expose storage differently: file-level access versus block-level access. The workload and operational model determine the right fit.
Frequently asked questions
Is iSCSI NAS or SAN?
iSCSI transports block storage over IP and is normally considered a SAN technology.
Can a NAS host virtual machines?
Yes. Hypervisors can use NFS or SMB-based datastores where supported, so virtualization does not automatically require SAN block storage.
Which is faster, NAS or SAN?
Neither is inherently always faster. Performance depends on media, controllers, network design, protocol implementation and workload.