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Block Storage over a Network

Present remote storage to a host as a block device by carrying block I/O requests, data, and completion status across a network.

Version
v1 · 2026-10-03 · History
Domain-specific #
13019
Domain group
Applied Sciences & Engineering
Origin domain
Computer Science & Software Engineering
Aliases
Networked Block Storage, Remote Block Storage

Core Idea

Block storage over a network lets a host issue block-device reads and writes against remote backing capacity. Requests cross a network to a target, which returns data and completion status. The stable identity is a client-visible block interface plus remote request/response path, not one protocol, address scheme or transport.[ref-2041391d6be5][ref-7b58136a7117]

Scope of Application

iSCSI transports SCSI commands over TCP between initiator and target. Linux NBD presents remote capacity as /dev/nb0 and sends block requests over TCP; its client may put a filesystem on the exposed device. NVMe-oF is another command-family variant, moving NVMe commands across network fabrics. None makes ATA over Ethernet's raw-layer-2 restriction universal.[ref-2041391d6be5][ref-7b58136a7117][^ref-6222c611afaf]

Clarity

A file share asks a server for named files; network block storage exposes a device to the client storage stack. NBD documentation explicitly contrasts it with NFS. NBD also shows why “unchanged disk commands across the wire” is too narrow as a universal definition. A block endpoint does not by itself guarantee multi-host filesystem coherence or failover.[^ref-7b58136a7117]

Manages Complexity

The role map—host block endpoint / initiator / network / target / completion—supports comparison across iSCSI and NBD while preserving their different command semantics. It also separates the local-looking host interface from remote network and target failure domains.[ref-2041391d6be5][ref-7b58136a7117]

Abstract Reasoning

Trace one host read: determine whether it begins at a block-device interface, becomes a network request, reaches backing capacity and returns data/status. If the host instead issues only named-file requests, the system is a network file service. If no network-separated target completes the I/O, it is not block storage over a network. Security, recovery and shared-write guarantees require separate evidence.[ref-2041391d6be5][ref-7b58136a7117]

Knowledge Transfer

iSCSI carries SCSI semantics over TCP; NBD sends its own block requests over TCP. Both preserve a remote host-visible block device, but neither shares every wire format with NVMe-oF or ATA over Ethernet.

[^ref-2041391d6be5]: M. Chadalapaka, J. Satran, K. Meth and D. Black, RFC 7143, Internet Small Computer System Interface (iSCSI) Protocol (Consolidated) (IETF, 2014), abstract and §4. [^ref-7b58136a7117]: Linux kernel documentation, “Network Block Device (TCP version),” Overview. [^ref-6222c611afaf]: NVM Express, “NVMe over Fabrics (oF) Specification (historical reference only),” historical-reference description.

Neighborhood in Abstraction Space

Block Storage over a Network sits in a sparse region of the domain-specific corpus (67th percentile for distinctiveness): few abstractions share its structure, so a faithful description tends to retrieve it precisely.

Family — Network Security Vulnerabilities & Trust (26 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-10-08