SAN (Storage Area Network)
Definition
A SAN is a dedicated, high-speed network that provides block-level storage access to servers. Unlike NAS (which serves files), a SAN presents remote storage as locally attached disks to the server, enabling features like live migration and clustered file systems.
SANs use protocols like Fibre Channel (FC) or iSCSI (over TCP/IP) and are common in enterprise data centers for databases, virtualization, and high-performance computing.
Key Concepts
- Protocols: Fibre Channel (FC), iSCSI, FCoE (Fibre Channel over Ethernet)
- Architecture: Switched fabric, point-to-point, or circular topology
- Zoning/LUN masking: Access control at the SAN level
- Multipathing: Redundant paths for fault tolerance
NAS vs SAN
| Feature | NAS | SAN |
|---|---|---|
| Access level | File-level | Block-level |
| Protocol | NFS, SMB/CIFS | FC, iSCSI |
| Latency | Higher | Lower |
| Management | Simpler | Complex |
| Use case | File sharing, backups | Databases, VMs |