Users guide

11 Intel® RAID Software User Guide
2.2.2 RAID 1 - Disk Mirroring/Disk Duplexing
In RAID 1, the RAID controller duplicates all data from one drive to a second drive.
RAID 1 provides complete data redundancy, but at the cost of doubling the required data
storage capacity. Table 2 provides an overview of RAID 1.
Table 2. RAID 1 Overview
Figure 2. RAID 1 – Disk Mirroring/Disk Duplexing
2.2.3 RAID 5 - Data Striping with Striped Parity
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 detects 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 I/O transactions simultaneously.
RAID 5 addresses the bottleneck issue for random I/O operations. Because each drive
contains both data and parity, numerous writes can take place concurrently.
Weak Points
Does not provide fault tolerance or high bandwidth. If any drive fails, all
data is
lost.
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
a
pplication that requires fault tolerance and minimal capacity.
Weak Points
Requires twice as many disk drive
s. Performance is impaired during
drive rebuilds.
Drives
2 to 32 (must be an even number of drives)
RAID Adapter
ABC
A
B
C
A
B
C
Disk Mirroring
RAID 1
Available Capacity
N=# disks
C = Disk Capacity
Available Capacity =
(N*C) /2
RAID 1