SMB and NFS are file-sharing protocols — they hand out folders that multiple computers browse and edit, like a shared drive. iSCSI is different: it hands one computer a raw block of storage to mount as if it were a local, private hard drive. SMB is Windows-native, NFS is Linux/Unix-native, and iSCSI works with either, since the receiving computer just sees a disk.
SMB — The Windows-Native File Share
Server Message Block (SMB) is the protocol behind "mapping a network drive" on Windows — it is also what macOS and most modern NAS software speak when browsing a shared folder from a Mac. The NAS presents named shares (like Photos or Projects), and any authorized computer on the network can open, edit, and save files inside them just like a local folder, with per-user or per-group permissions enforced by the NAS. SMB is by far the most common protocol on small-office and home NAS setups precisely because it needs no configuration on the client side beyond typing in a network address — it is the default, and for most people it is also the right answer.
NFS — The Unix/Linux-Native File Share
Network File System (NFS) does the same conceptual job as SMB — sharing folders over the network — but grew up in the Unix and Linux world and remains the native choice there. Linux servers, many media-server and virtualization platforms, and Unix-based tools generally mount NFS shares more natively and efficiently than SMB ones. It shows up constantly behind the scenes: a Plex or virtualization host running on Linux, or a render farm of Linux machines, will typically reach a NAS over NFS rather than SMB even when both are available, because the permission model and performance characteristics line up better with how those systems already work.
iSCSI — Block Storage, a Different Animal Entirely
iSCSI (Internet Small Computer System Interface) does not share files or folders at all. It presents a chunk of raw storage capacity over the network as a "target," and the connecting computer formats and treats it exactly like an internal drive — complete with its own file system that only that one computer understands at a time. This makes iSCSI the protocol of choice for virtual machine storage, database volumes, and any workload that wants block-level access rather than a shared folder. The tradeoff is exclusivity: unlike SMB or NFS, an iSCSI volume is not meant to be opened by several computers simultaneously the way a shared folder is — doing so without cluster-aware software risks corrupting the file system on it.
Picking Between Them for a Home or Small-Office NAS
Most multi-bay NAS platforms, including the Synology DS423 and the enterprise-leaning Synology DS923+, support all three protocols simultaneously, so the real decision is per-use-case rather than picking one protocol for the whole box:
- Everyday file sharing across a mixed household or small office: SMB — it just works on Windows and Mac with no extra setup
- Feeding a Linux media server, virtualization host, or render node: NFS, for native performance and permission handling on that side
- Storage for a virtual machine or a database that needs its own dedicated volume: iSCSI, treated as a private disk rather than a shared folder
- A small business running several VMs against shared storage: a rack-mount unit like the Synology RS822RP+ commonly serves iSCSI targets to a hypervisor host while still offering SMB shares to office staff on the same box
None of this changes how a NAS should be sized or protected in the first place — see our guide to setting up a NAS for media storage and backup for the broader setup picture, and choosing a NAS for photo and video work if the workload is creative rather than IT infrastructure.
Frequently Asked Questions
Can I use SMB and NFS on the same NAS at the same time?
Yes — most NAS platforms run both services concurrently and can even expose the same underlying folder through both protocols, though mixed simultaneous access to identical files from both protocols at once can create permission-mapping quirks worth testing before relying on it.
Is iSCSI faster than SMB or NFS?
Block storage generally has lower overhead than file-sharing protocols for the specific workloads it targets (databases, VM disks), but "faster" is workload-dependent, not a fixed universal ranking, and network speed and drive type matter more than protocol choice in most everyday comparisons.
Do I need iSCSI for a home NAS?
Almost never. iSCSI solves problems specific to virtualization and dedicated application storage. A home or small-office NAS used for file sharing, photo/video libraries, and backups is well served by SMB (and NFS if any Linux devices are involved).
Which protocol should a Mac use?
Modern macOS supports SMB natively and it is the recommended default for connecting to a NAS — the older Apple-specific AFP protocol has been phased out industry-wide in favor of SMB.
Share this article: Twitter