What does SAN stand for?
SAN stands for Storage Area Network. A dedicated high-speed network that gives servers block-level access to shared storage, so the storage appears as a local disk. It uses Fibre Channel or iSCSI; a NAS, by contrast, shares files over the regular network with SMB or NFS.
A SAN is a dedicated high-speed network that connects servers to shared storage arrays. The array presents volumes as raw blocks, and each server formats and uses its volume as if it were a local disk. Fibre Channel is the classic SAN transport; iSCSI carries the same block commands over ordinary IP networks. SANs are used where many servers need fast, centrally managed storage, for example for virtual machines and databases.
SAN in practice: an example
A cluster of virtualization hosts stores every virtual machine's disk on one array reached over the SAN. When a host fails, another host mounts the same volumes and restarts the machines, because the storage was never inside the failed server.
What SAN is confused with
SAN vs NAS: what is the difference?
A SAN delivers blocks, a NAS delivers files. With a SAN the server owns the file system; with a NAS the storage device does. What NAS stands for
SAN vs Subject Alternative Name: what is the difference?
In a certificate, SAN means Subject Alternative Name, the field that lists the host names the certificate is valid for. On the Network+ and A+ acronym lists, SAN is the storage network.
Which exams cover SAN?
SAN is on the official CompTIA acronym list for two of the four exams covered here.
- Network+ N10-009: 1.0 (Networking Concepts).
- A+ 220-1201 and 220-1202: 220-1201 2.0 (Networking).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. A database server needs a volume it can format with its own file system, with the disks living in a shared array. Which technology provides it?
- A storage area network
- A network-attached storage share
- A print server
- A content delivery network
Show the answer
A. A storage area network. Block-level volumes that the server formats itself are what a SAN delivers. A NAS share arrives already formatted and is accessed file by file.
2. Which protocol carries SAN block storage over a standard IP network?
- iSCSI
- SMTP
- SNMP
- TFTP
Show the answer
A. iSCSI. iSCSI wraps SCSI block commands in TCP/IP so a SAN can run on Ethernet. The others are mail, management and file-transfer protocols.
Sources: NIST glossary: storage area network; RFC 7143: Internet Small Computer System Interface (iSCSI) Protocol (Consolidated); RFC 5280: Internet X.509 Public Key Infrastructure Certificate and CRL Profile. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 11 November 2026.