Data Center Storage Explained

Key Concepts

• Storage Types
• Storage Area Network (SAN)
• Network Attached Storage (NAS)
• Redundant Array of Independent Disks (RAID)
• Storage Performance Metrics

Storage Types

Data center storage can be categorized into several types based on their access methods and technologies. These include:

• Direct Attached Storage (DAS): Storage devices directly connected to a server. Think of it as a personal computer with an internal hard drive.
• Storage Area Network (SAN): A dedicated network that provides block-level storage to servers. Imagine a high-speed highway dedicated to transporting data between servers and storage devices.
• Network Attached Storage (NAS): Storage devices connected to a network, providing file-level storage. Consider it as a shared folder on a network drive accessible to multiple users.

Storage Area Network (SAN)

A SAN is a high-speed network that enables the aggregation of storage resources and provides block-level storage to servers. Key components include:

• Fibre Channel (FC): A high-speed network technology commonly used in SANs, operating at speeds like 16 Gbps or 32 Gbps.
• iSCSI: A protocol that allows IP-based storage networking, enabling Ethernet to be used for SAN connectivity, reducing costs and complexity.

Think of a SAN as a specialized data highway that ensures fast and reliable data transfer between servers and storage devices, much like a dedicated express lane on a congested road.

Network Attached Storage (NAS)

NAS devices provide file-level storage over a network, making them accessible to multiple users and applications. Key features include:

• File Sharing: NAS devices support file sharing protocols like NFS (Network File System) and SMB (Server Message Block).
• Scalability: NAS systems can be easily scaled by adding more storage devices to the network.

Consider NAS as a shared folder on a network drive that multiple users can access simultaneously, similar to a communal library where everyone can borrow and return books.

Redundant Array of Independent Disks (RAID)

RAID is a data storage virtualization technology that combines multiple physical disk drive components into one or more logical units for redundancy and performance. Common RAID levels include:

• RAID 0: Provides data striping across disks for increased performance but no redundancy.
• RAID 1: Mirrors data across disks for redundancy but no performance gain.
• RAID 5: Provides data striping with distributed parity for both performance and redundancy.
• RAID 6: Similar to RAID 5 but with dual parity for enhanced redundancy.

Think of RAID as a way to combine multiple hard drives into a single, more reliable and faster storage unit, much like combining multiple lanes on a highway to increase traffic flow and safety.

Storage Performance Metrics

Understanding storage performance metrics is crucial for optimizing data center operations. Key metrics include:

• IOPS (Input/Output Operations Per Second): Measures the number of read and write operations a storage device can perform in one second.
• Throughput: Measures the amount of data transferred between storage devices and servers over a period.
• Latency: Measures the time it takes for a storage device to respond to a request.

Visualize these metrics as the speed, capacity, and responsiveness of a data highway, where IOPS is the number of cars passing through, throughput is the total amount of cargo transported, and latency is the time it takes for a car to reach its destination.