span
also: SPAN, switched port analyzer, disk span
In RAID and storage contexts, a span is a single physical drive or a set of drives treated as one logical unit. In networking, it refers to a Virtual LAN (VLAN) segment or the range of network interfaces a bridge connects.
A span in Linux storage typically describes one drive in a RAID array or a contiguous group of drives functioning together. For example, in RAID 0 or RAID 1, each physical disk may be called a span, or multiple disks can form a single logical span depending on the RAID controller's configuration.
In networking, span commonly refers to a switched port analyzer (SPAN) feature that copies traffic from monitored ports to a destination port for analysis. This is essential for network troubleshooting: a network administrator might span traffic from a production switch port to a packet capture interface to monitor suspicious connections.
You may also encounter span in the context of Virtual LANs (VLANs), where it describes the physical extent of a VLAN across multiple switches, or in the Linux bridge command output showing connected interfaces.