Module 2-1a

Server Hardware Overview

• Modern server hardware is designed for multiple users, applications, processors, and fault tolerance.

Storage Types/Connections

• SATA (Serial Advanced Technology Attachment) is a hard drive interface that offers faster transfer times, thinner and more flexible cabling, and easier plug-and-play connections.
  • Each SATA device connects directly to the SATA controller's host adapter, eliminating daisy-chaining.
  • Data is transferred in serial bursts, offering faster data transfer than parallel devices.
• NAS (Network-Attached Storage) is a device or group of devices that provides centralized and fault-tolerant data storage for a network.
  • NAS maintains its own interface to the Local Area Network (LAN), making it independent of servers for network connectivity.
  • NAS allows multiple clients on a network to access the same files.
  • NAS serves as an independent network node with its own IP address.
• SAN (Storage Area Network) is a high-speed network dedicated to storage devices and switches, connected to servers and computer systems.
  • It presents a shared pool of storage devices to multiple servers.
  • SAN supports centralized storage management, enabling easier data transfer between devices, data sharing, and backup and restoration processes.
  • It offers high fault tolerance due to data redundancy.
  • SANs are typically built with fiber-optic media, providing high speeds and using protocols like Fibre Channel.
  • SANs are scalable and can easily accommodate additional storage and devices without interrupting network activity.
  • SANs are ideal for environments with large amounts of data requiring constant availability.

Configure System Storage

Redundant Array of Independent Disks (RAID)

• RAID is a technology that enhances data storage and retrieval capabilities and provides fault tolerance by mitigating data loss due to hardware failures.
• Hardware RAID uses a dedicated RAID disk controller that manages the RAID array independently of the server.
• Software RAID relies on software to implement and manage RAID techniques, reducing costs by eliminating specialized controllers and hardware.

RAID Levels

• RAID 0 (Disk Striping):
  • Provides striping without any parity or mirroring, dividing data across multiple disks.
  • This enhances performance but sacrifices fault tolerance.
• RAID 1 (Disk Mirroring/Duplexing):
  • Focuses on fault tolerance by creating identical copies of data on separate disks.
  • Offers limited performance improvements for read operations, but writing data is slower as it must be written to multiple disks.
• RAID 5 (Disk Striping with Distributed Parity):
  • Stripes both data and parity information across multiple drives.
  • Offers good read/write speeds, cost-effectiveness, and decent capacity.
  • Less efficient for large data transfers.
• RAID 6 (Disk Striping with Dual Distributed Parity):
  • Extends RAID 5 by adding a second parity block, enhancing fault tolerance by allowing data recovery even after two concurrent disk failures.
  • Strong performance for read operations and good for large data transfers, but slower for small transfers.
• RAID 0+1/1+0/RAID 10 (Striping and Mirroring Combined):
  • Combine the benefits of RAID 0 and RAID 1, aiming for both high performance and fault tolerance.
  • RAID 10 uses a two-stage virtualisation hierarchy with at least four physical hard disks, striping in the first stage and mirroring in the second, creating a single virtual, fast, and fault-tolerant hard disk.