Owner's Manual

LSI SAS RAID ▍
MS-96E0
B-3
LSI SAS RAID ▍
MS-96E0
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) feature
-- 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.
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 vol
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ume to be easily restored by simply swapping disks. The rmware then automatically
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 congured on the controller. The hot spare makes the Integrated
Mirroring volume even more fault-tolerant.
Note: You can congure 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 eliminates
the need for complex backup software or expensive RAID hardware. The IM feature
operates independently from the operating system, in order to conserve system re
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sources. The BIOSbased conguration utility makes it easy to congure 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.
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