Lenovo ThinkServer RD650, User Manual

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LSI Corporation
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12Gb/s MegaRAID SAS Software User Guide

March 2014
Chapter 1: Overview
Dimmer Switch Features
you can choose whether to mix SAS and SATA HDD drives with SAS and SATA CacheCade software devices in various
combinations.
NOTE Support for SATA SSD drives applies only to those drives that support
ATA-8 ACS compliance.
1.4.1 SSD Guard
SSD Guard, a feature that is unique to MegaRAID, increases the reliability of SSDs by automatically copying data from a
drive with potential to fail to a designated hot spare or newly inserted drive. Because SSDs are more reliable than hard
disk drives (HDDs), non-redundant RAID 0 configurations are much more common than in the past. SSD Guard offers
added data protection for RAID 0 configurations.
SSD Guard works by looking for a predictive failure while monitoring the SSD Self-Monitoring, Analysis, and Reporting
Technology (S.M.A.R.T.) error log. If errors indicate that a SSD failure is imminent, the MegaRAID software starts a
rebuild to preserve the data on the SSD and sends appropriate warning event notifications.
1.5 Dimmer Switch Features
Powering drives and cooling drives represent a major cost for data centers. The MegaRAID Dimmer Switch feature set
reduces the power consumption of the devices connected to a MegaRAID controller. This helps to share resources
more efficiently and lowers the cost.
Dimmer Switch I – Spin down unconfigured disks. This feature is configurable and can be disabled.
Dimmer Switch II – Spin down Hot Spares. This feature is configurable and can be disabled.
1.6 UEFI 2.0 Support
UEFI 2.0 provides MegaRAID customers with expanded platform support. The MegaRAID UEFI 2.0 driver, a boot
service device driver, handles block IO requests and SCSI pass-through (SPT) commands, and offers the ability to
launch pre-boot MegaRAID management applications through a driver configuration protocol (DCP). The UEFI driver
also supports driver diagnostic protocol, which allows administrators to access pre-boot diagnostics.
1.7 Configuration Scenarios
You can use the SAS RAID controllers in three scenarios:

Low-end, Internal SATA II Configurations
In these configurations, use the RAID controller as a high-end SATA II-compatible controller that connects up to 8
disks either directly or through a port expander. These configurations are mostly for low-end or entry servers.
Enclosure management is provided through out-of-band Inter-IC (I
2
C) bus. Side bands of both types of internal
SAS connectors support the SFF-8485 (SGPIO) interface.

Midrange Internal SAS Configurations
These configurations are like the internal SATA II configurations, but with high-end disks. These configurations are
more suitable for low-range to midrange servers.

High-end External SAS/SATA II Configurations