Introduction; Concepts Of High-Availability Das - Intel RAID High Availability Storage User Manual

1. Introduction

This document explains how to set up and configure the hardware and software for the Intel
RAID High Availability Storage solution.
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The Intel RAID High Availability Storage solution provides fault tolerance capabilities as a key
part of a high-availability data storage system. The RAID High Availability Storage solution
combines redundant Intel
expanders, and dual-port SAS drives to provide failover redundancy through multiple paths to
data.
The redundant components and software technologies provide a high-availability system with
ongoing service that is not interrupted by the following events:
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A node failure which does not interrupt service because the configuration has multiple
nodes with cluster failover.
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An expander failure which does not interrupt service because the dual expanders in every
enclosure provide redundant data paths.
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A drive failure which does not interrupt service because RAID fault tolerance is part of the
configuration.

A system storage expansion or maintenance activity that can be completed without
requiring an interruption of service because of redundant components, management
software, and maintenance procedures.

Concepts of High-Availability DAS

In terms of data storage and processing, High Availability (HA) means a computer system
design that ensures a high level of operational continuity and data access reliability over a given
period of time. DAS means Directly Attached Storage. High-availability systems are critical to
the success and business needs of small and medium-sized businesses such as retail and
health care offices. An Intel® RAID High Availability Storage solution enables a customer to
maintain all elements of the high-availability system, with shared direct-attached drives
accessible to multiple servers through the use of failover clustering technology.
Simply defined, a cluster is a group of computers working together to run a common set of
applications and to present a single logical system to the client and application. Failover
clustering provides redundancy to the cluster group to maximize solution up-time by utilizing
fault-tolerant components. In the example of two servers with shared storage that comprise a
failover cluster, when a server fails, the failover cluster automatically moves control of the
shared resources to the surviving server with no interruption of access to data. This
configuration allows seamless failover capabilities in the event of planned failover (maintenance
mode) for maintenance or upgrade, or in the event of a failure of a system component such as a
failure of the CPU, memory, or other non-storage hardware.
SAS zoning is typically required to partition the storage domain between multiple initiators and
target devices. However, because multiple initiators can exist in a common shared storage
domain, there is a concept of device reservations in which physical drives, drive groups, and
Intel® RAID High Availability Storage User Guide
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RAID controllers, computer nodes, cable connections, SAS
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