3-1-3 Storage Area Network (SAN) Explained
Key Concepts
- Storage Area Network (SAN)
- Fibre Channel (FC)
- iSCSI (Internet Small Computer System Interface)
- Block-Level Storage
- SAN Components
Storage Area Network (SAN)
A Storage Area Network (SAN) is a dedicated high-speed network that provides block-level storage to servers. SANs are designed to enable multiple servers to access shared storage devices, such as disk arrays and tape libraries, as if they were locally attached. This allows for centralized storage management and high availability.
Fibre Channel (FC)
Fibre Channel (FC) is a high-speed data transfer protocol that is commonly used in SANs. It provides low-latency, high-bandwidth connections between storage devices and servers. Fibre Channel networks use a topology such as Fibre Channel over Ethernet (FCoE) or Fibre Channel over IP (FCIP) to extend the reach of the SAN.
iSCSI (Internet Small Computer System Interface)
iSCSI is a storage networking standard that allows block-level storage to be accessed over an IP network. It enables the use of existing Ethernet infrastructure for SAN connectivity, reducing the need for specialized Fibre Channel hardware. iSCSI is often used in environments where cost and simplicity are more important than raw performance.
Block-Level Storage
Block-level storage is a method of storing data in fixed-size blocks, each with its own address. This allows for efficient data access and manipulation, as each block can be read or written independently. Block-level storage is commonly used in SANs because it provides high performance and flexibility for various applications.
SAN Components
A typical SAN consists of several key components:
- Storage Devices: These include disk arrays, tape libraries, and other storage media that hold the data.
- Switches: Fibre Channel switches or Ethernet switches that facilitate communication between storage devices and servers.
- Host Bus Adapters (HBAs): These are specialized network interface cards that connect servers to the SAN.
- Routers and Gateways: These devices extend the SAN's reach and provide connectivity between different SANs or between SANs and other networks.
Examples and Analogies
Think of a SAN as a high-speed, dedicated highway system for data. Fibre Channel is like a high-speed express lane that ensures quick and reliable data transfer. iSCSI is like a standard highway that uses existing road infrastructure, making it more cost-effective but potentially slower. Block-level storage is like having individual mailboxes for each piece of data, allowing for efficient and direct access.
Another analogy is a professional courier service. Fibre Channel is like a dedicated, high-speed courier that delivers packages quickly and reliably. iSCSI is like a standard delivery service that uses existing transportation networks, making it more accessible but potentially slower. Block-level storage is like having individual lockers for each package, ensuring efficient and organized delivery.