2-3 Storage Infrastructure Explained

Key Concepts

• Storage Types
• Storage Area Network (SAN)
• Network Attached Storage (NAS)
• Storage Protocols
• Data Redundancy and Replication

Storage Types

Storage types refer to the different methods and technologies used to store data. Common storage types include:

• Direct Attached Storage (DAS): Storage devices directly connected to a server. Example: A hard drive inside a server.
• Storage Area Network (SAN): A dedicated network that provides block-level storage to servers. Example: Fibre Channel SAN.
• Network Attached Storage (NAS): Storage devices connected to a network that provide file-level storage. Example: A NAS device connected to a LAN.

Storage Area Network (SAN)

A SAN is a high-speed network that enables the aggregation of storage into a centralized resource accessible to multiple servers. SANs use block-level storage protocols like Fibre Channel (FC) and iSCSI to provide low-latency, high-performance storage solutions.

Example: A data center uses a Fibre Channel SAN to provide storage to multiple servers. The SAN includes a storage array and Fibre Channel switches, allowing servers to access shared storage resources efficiently.

Network Attached Storage (NAS)

NAS devices are storage appliances connected to a network that provide file-level storage services. NAS uses file-level protocols like NFS and SMB/CIFS to share files across the network. NAS is ideal for environments requiring shared file access and collaboration.

Example: A company uses a NAS device to share files among employees. The NAS device is connected to the LAN, and users can access shared folders using NFS or SMB/CIFS protocols.

Storage Protocols

Storage protocols define the methods and standards used for data transfer between storage devices and servers. Key protocols include:

• Fibre Channel (FC): A high-speed network protocol used primarily for SANs. Example: FC-AL (Fibre Channel Arbitrated Loop).
• iSCSI (Internet Small Computer System Interface): A protocol that allows SCSI commands to be sent over IP networks. Example: iSCSI targets and initiators.
• NFS (Network File System): A protocol for sharing files over a network. Example: NFSv4.
• SMB/CIFS (Server Message Block/Common Internet File System): A protocol for sharing files, printers, and other resources. Example: SMB 3.0.

Data Redundancy and Replication

Data redundancy and replication involve creating multiple copies of data to ensure availability and protect against data loss. Techniques include:

• RAID (Redundant Array of Independent Disks): A method of combining multiple disks to provide redundancy and improve performance. Example: RAID 5 provides parity and redundancy with three or more disks.
• Data Replication: The process of copying data to multiple locations. Example: Real-time replication to a secondary storage array in a different data center.
• Snapshots and Clones: Techniques for creating point-in-time copies of data. Example: A snapshot of a database before performing a major update.