Lenovo ThinkServer RD650, User Manual

Page: 29 / 418

LSI Corporation
- 29 -
12Gb/s MegaRAID SAS Software User Guide

March 2014
Chapter 2: Introduction to RAID
RAID Levels
Table 7 RAID 0 Overview
Figure 7 RAID 0 Drive Group Example with Two Drives
2.2.4 RAID 1
In RAID 1, the RAID controller duplicates all data from one drive to a second drive in the drive group. RAID 1 supports
an even number of drives from 2 through 32 in a single span. RAID 1 provides complete data redundancy, but at the
cost of doubling the required data storage capacity. The following table provides an overview of RAID 1. The following
figure provides a graphic example of a RAID 1 drive group.
Table 8 RAID 1 Overview
Figure 8 RAID 1 Drive Group
Uses Provides high data throughput, especially for large files. Any environment that does not require fault tolerance.
Strong points Provides increased data throughput for large files.
No capacity loss penalty for parity.
Weak points Does not provide fault tolerance or high bandwidth.
All data is lost if any drive fails.
Drives 1 to 32
Uses Use RAID 1 for small databases or any other environment that requires fault tolerance but small capacity.
Strong points Provides complete data redundancy. RAID 1 is ideal for any application that requires fault tolerance and
minimal capacity.
Weak points Requires twice as many drives. Performance is impaired during drive rebuilds.
Drives 2 through 32 (must be an even number of drives)
?
3EGMENT
3EGMENT
3EGMENT
3EGMENT 3EGMENT
3EGMENT
3EGMENT
3EGMENT
?
2!)$
3EGMENT 3EGMENT
$UPLICATE
3EGMENT 3EGMENT
$UPLICATE
2!)$
3EGMENT 3EGMENT
$UPLICATE
3EGMENT 3EGMENT
$UPLICATE
2!)$
3EGMENT 3EGMENT
$UPLICATE
3EGMENT 3EGMENT
$UPLICATE
2!)$
3EGMENT 3EGMENT
$UPLICATE
3EGMENT 3EGMENT
$UPLICATE