Performance Support

Storage: SAN Components & Interconnections

TranscriptMuch like a Local Area Network or LAN a SAN is a Storage Area Network. It consists of networking components and attached devices. A SAN consists of storage networking devices like switches SAN storage devices like SAN arrays and SAN attached host computer systems like application servers.

A SAN often utilizes Fibre Channel fabric technologies. This is an infrastructure specifically designed to handle storage communications, it provides fast and reliable access to storage and is therefore very well suited for performance oriented workloads with high availability needs. The SAN fabric is similar in concept to a network segment on a Local Area Network. A typical Fibre Channel SAN fabric is made up of a number of Fibre Channel switches and/or Fibre Channel routers.

In order to demonstrate the components of a SAN in the way that it will make the most sense, I'll draw out the basics of a Local Area Network to help reinforce the concepts and ideas.

A LAN typically consists of client computers connected to Ethernet switches with Ethernet patch cables connected to internal Network Interface Cards or NICs. The servers on the LAN are connected in the same fashion. And devices are able to communicate to each other over the network. In SAN there are also client devices but in this case we're talking about SAN attached host servers in most cases. The servers are also connected to SAN switches, in this case Fibre Channel switches, and instead of using network interface cards and patch cables the servers use Host Bus Adapter cards and are connected with fiber patch cables.

Instead of servers communicating to other servers over the SAN they communicate to the SAN storage devices. The SAN storage devices are connected to the SAN in the same way that the SAN attached host are connected using fiber patch cables to attach to the Fibre Channel switches. However, rather than installing HBA cards in the SAN storage device, they already have connections built into the SAN storage devices called storage processors or SPs. So at this point we have a SAN, one or more host computer systems, and one or more SAN storage devices both connected to one or more Fibre Channel switches in the middle. Now the storage from the SAN storage device can be made accessible to the SAN attached host server, and the server operating system sees the storage as local disk.

That is SAN components and interconnections. Thanks for watching.

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