Compaq 3000 User Manual

Page 48

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Chapter 2. RAID Array Controller

EK–SMCPQ–UG. C01

2–15

Figure 2–9 Diagram of a RAID 5 Write

1101
0110
1011
0010

0111
1110

0001
0110

Host Data

Controller divides the

data into chunksized units

and calculates parity

There is still data left

so the Controller

repeats the Process

1101

1011

0111

0111

0110

0110

1110

1110

1011

1011

0001

0001

0010

0010

0110

0110

Striped data and parity
written to the array

Striped data
written to the array

SHR-1058

0010

1110

XOr

XOr

Parity =

Parity =

and parity

RAID 5 handles drive failures in the same manner as RAID 4, except the parity
is different for each stripe. The controller either uses the parity information on a
stripe to reconstruct its data or simply reads the data as normal, depending on the
location of the stripe’s parity drive.

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