AMCC SIDECAR 3 - Manual (Page 15)

Red Hot RAID 6
The fastest RAID 6 available
RAID 6 eliminates the risk of data loss if a second hard disk drive fails
while the RAID array is rebuilding. In a 3ware RAID 6 system, two sets
of parity are calculated, written, and rotated across all the drives.
This second simultaneous P + Q parity calculation allows the array
to survive up to two drive failures without losing data, for significantly
improved fault tolerance. RAID 6-enabled 9650SE controllers deliver
unequaled RAID 6 performance.
RAID 6 represents a sea change in the RAID landscape. It provides
the industry with higher levels of data protection, data availability and
fault tolerance than RAID 5. By assuring data availability following a
second drive failure, users can rest assured that they are enjoying
maximum data protection, both in normal and degraded modes.
And, with RAID 6 enabled 3ware controllers, RAID 6 will not cripple
performance.
RAID 6 Enabled 3ware Controllers
• 9650SE-8LPML
• 9650SE-12ML
• 9650SE-16ML
• 9650SE-24M8
3ware RAID 6: Two sets of parity data, P + Q, are striped across
disks. RAID 6 safeguards against data loss during rebuild mode
by allowing up to two consecutive drive failures for maximum
fault tolerance.
• High capacity systems with eight or more
high capacity drives
• For enterprise/mission critical installations
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
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