Integrated Mirroring Overview; Introduction - MSI MS-9282 User Manual

2. Integrated Mirroring Overview

This section provides an overview of the LSI Logic Integrated Mirroring (IM) feature.

2.1 Introduction

As a result of the shift towards Network Attached Storage (NAS), ISPs need a cost
effective, fault-tolerant solution to protect the operating systems on small form factor,
high-density, rack-mountable servers. The LSI Logic Integrated Mirroring (IM) fea-
ture—which includes Integrated Mirroring Enhanced (IME)—provide data protection
for the system boot volume to safeguard critical information such as the operating
system on servers and high performance workstations. The Integrated Mirroring
feature gives customers a robust, high-performance, fault-tolerant solution to their
storage needs, at a lower cost than a dedicated RAID controller.
The Integrated Mirroring feature supports simultaneous mirrored volumes with two
disks (IM) or three to eight disks (IME), to provide fault-tolerant protection for critical
data. (If a hot spare disk is used, the maximum volume size is seven mirrored disks,
plus the hot spare disk.) Up to two IM volumes are supported per SAS controller, with
up to ten drives total per controller.
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Note: Ten disk drives is the theoretical upper limit, although the SAS controller
itself may support fewer drives.
If a disk in an Integrated Mirroring volume fails, the hot swap capability allows the
volume to be easily restored by simply swapping disks. The firmware then automati-
cally re-mirrors the swapped disk. Additionally, each SAS controller can have one
global hot spare disk available to automatically replace a failed disk in the one or two
IM or IME volumes configured on the controller. The hot spare makes the Integrated
Mirroring volume even more fault-tolerant.
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Note: You can configure an Integrated Mirroring volume and an Integrated Striping
volume on the same LSI Logic SAS controller.
The IM feature uses the same device drivers as the standard LSI Logic Fusion-MPT
based controllers, providing seamless and transparent fault tolerance. This elimi-
nates the need for complex backup software or expensive RAID hardware. The IM
feature operates independently from the operating system, in order to conserve
system resources. The BIOSbased configuration utility makes it easy to configure IM
and IME volumes.
The Integrated Mirroring feature is currently available as an optional component of
the Fusion-MPT architecture on LSI Logic controller products.
LSI SAS RAID
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