Lenovo ThinkServer RD240 MegaRAID SAS Software User Guide - Page 51

RAID 1, RAID 1 Drive Group, Table 2.6, RAID 1 Overview

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2.5.4 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 to 32 in a single span. RAID 1 provides complete data redundancy, but at the cost of doubling the required data storage capacity. Table 2.6 provides an overview of RAID 1. Figure 2.6 provides a graphic example of a RAID 1 drive group. Table 2.6 RAID 1 Overview Uses Strong Points Weak Points Drives Use RAID 1 for small databases or any other environment that requires fault tolerance but small capacity. Provides complete data redundancy. RAID 1 is ideal for any application that requires fault tolerance and minimal capacity. Requires twice as many drives. Performance is impaired during drive rebuilds. 2 - 32 (must be an even number of drives) Figure 2.6 RAID 1 Drive Group Segment 1 Segment 1 Duplicate Segment 5 Segment 5 Duplicate ... Segment 2 Segment 2 Duplicate Segment 6 Segment 6 Duplicate ... RAID1 RAID1 Segment 3 Segment 3 Duplicate Segment 7 Segment 7 Duplicate ... RAID1 Segment 4 Segment 4 Duplicate Segment 8 Segment 8 Duplicate ... RAID1 2.5.5 RAID 5 RAID 5 includes disk striping at the block level and parity. Parity is the data's property of being odd or even, and parity checking is used to detect errors in the data. In RAID 5, the parity information is written to all drives. RAID 5 is best suited for networks that perform a lot of small input/output (I/O) transactions simultaneously. RAID Levels 2-19

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RAID Levels
2-19
2.5.4
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 to 32 in a single span. RAID 1 provides complete data
redundancy, but at the cost of doubling the required data storage
capacity.
Table 2.6
provides an overview of RAID 1.
Figure 2.6
provides
a graphic example of a RAID 1 drive group.
Figure 2.6
RAID 1 Drive Group
2.5.5
RAID 5
RAID 5 includes disk striping at the block level and parity. Parity is the
data’s property of being odd or even, and parity checking is used to
detect errors in the data. In RAID 5, the parity information is written to
all drives. RAID 5 is best suited for networks that perform a lot of small
input/output (I/O) transactions simultaneously.
Table 2.6
RAID 1 Overview
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 - 32 (must be an even number of drives)
Segment 1
Segment 1
Duplicate
Segment 2
Segment 3
Duplicate
Segment 4
Duplicate
Segment 3
Segment 4
Segment 5
Segment 6
Segment 7
Segment 8
Segment 5
Duplicate
Segment 6
Duplicate
Segment 7
Duplicate
Segment 8
Duplicate
Segment 2
Duplicate
...
...
...
...
RAID1
RAID1
RAID1
RAID1