AMCC SIDECAR 3 - Manual (Page 14)

Common RAID Levels
RAID 0, 1, 5, 10 and JBOD
Block 10
Block 7
Block 4
P1 Parity
Disk #1
Block 11
Block 8
P2 Parity
Q1 Parity
Disk #2
Block 12
P3 Parity
Q2 Parity
Block 1
Disk #3
Q4 Parity
Block 9
Block 6
Block 3
Disk #5
Striped Data with Distributed Double Parity — RAID 6
Host Data
P4 Parity
Q3 Parity
Block 5
Block 2
Disk #4
RAID 0 “Striping”
M
I
E
A
N
J
F
B
ETC. . .
L
H
D
O
K
G
C
RAID 1 “Mirroring”
D
C
B
A
D 1
C 1
B 1
A 1
=
RAID 5 “Rotational Parity”
3 Parity
A2
A1
A 0
B3
2 Parity
B1
B 0
D3
D2
D1
0 Parity
C3
C2
1 Parity
C 0
D2
D1 1
Drive 1
D2 1
D1
Drive 0
Drive 3 Drive 2
Stripe
RAID 10 "Striped Mirror"
SATA Disk
SATA Disk
SATA Disk
SATA Disk
Mirror
Block 10
Block 7
Block 4
P1 Parity
Disk #1
Block 11
Block 8
P2 Parity
Q1 Parity
Disk #2
Block 12
P3 Parity
Q2 Parity
Block 1
Disk #3
Q4 Parity
Block 9
Block 6
Block 3
Disk #5
Striped Data with Distributed Double Parity — RAID 6
Host Data
P4 Parity
Q3 Parity
Block 5
Block 2
Disk #4
RAID 0 “Striping”
M
I
E
A
N
J
F
B
ETC. . .
L
H
D
O
K
G
C
RAID 1 “Mirroring”
D
C
B
A
D 1
C 1
B 1
A 1
=
RAID 5 “Rotational Parity”
3 Parity
A2
A1
A 0
B3
2 Parity
B1
B 0
D3
D2
D1
0 Parity
C3
C2
1 Parity
C 0
D2
D1 1
Drive 1
D2 1
D1
Drive 0
Drive 3 Drive 2
Stripe
RAID 10 "Striped Mirror"
SATA Disk
SATA Disk
SATA Disk
SATA Disk
Mirror
Block 10
Block 7
Block 4
P1 Parity
Disk #1
Block 11
Block 8
P2 Parity
Q1 Parity
Disk #2
Block 12
P3 Parity
Q2 Parity
Block 1
Disk #3
Q4 Parity
Block 9
Block 6
Block 3
Disk #5
Striped Data with Distributed Double Parity — RAID 6
Host Data
P4 Parity
Q3 Parity
Block 5
Block 2
Disk #4
RAID 0 “Striping”
M
I
E
A
N
J
F
B
ETC. . .
L
H
D
O
K
G
C
RAID 1 “Mirroring”
D
C
B
A
D 1
C 1
B 1
A 1
=
RAID 5 “Rotational Parity”
3 Parity
A2
A1
A 0
B3
2 Parity
B1
B 0
D3
D2
D1
0 Parity
C3
C2
1 Parity
C 0
D2
D1 1
Drive 1
D2 1
D1
Drive 0
Drive 3 Drive 2
Stripe
RAID 10 "Striped Mirror"
SATA Disk
SATA Disk
SATA Disk
SATA Disk
Mirror
Hardware vs. Software RAID
All AMCC 3ware RAID controllers incorporate onboard processors to deliver true hardware RAID. Software RAID schemes use the system’s
processor, exploit host memory, compromise reliability and potentially rob the system of as much as 60% of its CPU cycles just to process
RAID calculations.
JBOD = Just a Bunch of Disks
• Applications requiring high bandwidth
performance but no fault tolerance
• Video production/editing
• Pre-press applications
• Provides fault tolerance and a read speed
advantage over non-RAID disks
• Applications requiring high availability
• Accounting
• Payroll
• Financial
• Most versatile RAID level providing performance,
fault tolerance and storage efficiency
• Video production/editing
• File and applications servers
• Database servers
• Email servers
• News servers
• Internet/Intranet
JBOD refers to an unconfigured disk attached to a RAID controller
• No fault tolerance
Block 10
Block 7
Block 4
P1 Parity
Disk #1
Block 11
Block 8
P2 Parity
Q1 Parity
Disk #2
Block 12
P3 Parity
Q2 Parity
Block 1
Disk #3
Q4 Parity
Block 9
Block 6
Block 3
Disk #5
Striped Data with Distributed Double Parity — RAID 6
Host Data
P4 Parity
Q3 Parity
Block 5
Block 2
Disk #4
RAID 0 “Striping”
M
I
E
A
N
J
F
B
ETC. . .
L
H
D
O
K
G
C
RAID 1 “Mirroring”
D
C
B
A
D 1
C 1
B 1
A 1
=
RAID 5 “Rotational Parity”
3 Parity
A2
A1
A 0
B3
2 Parity
B1
B 0
D3
D2
D1
0 Parity
C3
C2
1 Parity
C 0
D2
D1 1
Drive 1
D2 1
D1
Drive 0
Drive 3 Drive 2
Stripe
RAID 10 "Striped Mirror"
SATA Disk
SATA Disk
SATA Disk
SATA Disk
Mirror
• Data is first mirrored, then striped across across
the drives to provide double drive failure
protection without the parity calculation
performance penalty of RAID 5 and RAID 6.
The mirror provides the redundancy.
• Ability to recover from a drive failure in either
mirrored set