What Does Storage Area Network Topology (SAN Topology) Mean?
Storage area network (SAN) topology refers to the arrangement or configuration used by SANs. SANs typically use a fiber channel fabric topology, which is an infrastructure specifically engineered to manage storage communications. It offers more rapid and reliable access than the higher-level protocols used in network-attached storage (NAS). In concept, a fabric is identical to a network segment in a local area network (LAN). A standard fiber channel SAN fabric consists of several fiber channel switches.
Topology usually refers to the way the switches are interconnected, including ring, edge-core, core-edge or fully meshed.
Techopedia Explains Storage Area Network Topology (SAN Topology)
The standard SAN design consists of the following:
- Devices on the network's edge
- Switches in the network's core
- The cabling that links them all together
The suggested SAN topology for optimizing functionality, administration and scalability is a tiered, core-edge topology. This strategy delivers great performance without needless interconnections. At a higher level, the tiered topology includes a multitude of edge switches employed for device connectivity, plus a few of the core switches intended for routing traffic in between the edge switches.
- Edge-Core Topology - The edge-core topology positions storage (targets) on the core tier and initiators (servers) on the edge tier. As the storage and servers are on completely different switches, this topology provides easy administration and also good performance, with the majority of the traffic just traversing one hop from the edge to the core. The key drawback of this design is that the core connections and the storage are in contention for extension. This means that this topology provides only minimum growth.
- Edge-Core-Edge Topology - This topology positions initiators on an edge tier and storage on some other edge tier, leaving the core for switch interconnections or linking devices with network-wide scope, which include dense wavelength division multiplexers (DWDMs), storage virtualizers, inter-fabric routers, encryption engines and tape libraries. Since storage and servers are on totally different switches, this design facilitates independent scaling of storage and compute resources, simple management and optimum overall performance.
- Full-Mesh Topology - This topology lets users place storage and servers virtually anyplace as the communication involving source and destination is only one hop. Users are able to build a full-mesh topology, which is scalable and affordable, as opposed to the earlier generation of SAN solutions.