User's Guide

Chapter 1 DPM5500 System Description
Turning on the System
Quantum DPM5500 User’s Guide 8
frees up the concentration on a single drive, improving overall subsystem
throughput.
The RAID 5 parity encoding scheme maintains the system’s ability to
recover any lost data should a single drive fail. This can happen as long as
no parity stripe on an individual drive stores the information of a data
stripe on the same drive. In other words, the parity information for any
data stripe must always be located on a drive other than the one on which
the data resides (see figure 8
).
Figure 3 RAID 5 Configuration
Drive 0 Drive 1 Drive 2 Drive 3 Drive 4
A0 A1 A2 A3
1 parity
B0 B1 B2
2 parity
B4
C0 C1 3 parity C3 C4
D0
4 parity
D2 D3 D4
0 parity
E1 E2 E3 E4
Data stripe
Data stripe A
Data stripe B
Data stripe C
Data stripe D
Data stripe E
Turning on the System 1
To turn on the DPM5500 system (see figure 4):
1 Push the power button located on the front of the DPM5500.