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│
┌───────┴───────┐
│ Disk │
│ Controller │
└───────┬───────┘
│
│
┌────────────┼────────────┐
│ │ │
┌────┴─────┐ ┌────┴─────┐ ┌────┴─────┐
DATA │ AAA │ │ BBB │ │ CCC │
├──────────┤ ├──────────┤ ├──────────┤
DATA MIRROR │ CCC │ │ AAA │ │ BBB │
├──────────┤ ├──────────┤ ├──────────┤
DATA │ DDD │ │ EEE │ │ FFF │
├──────────┤ ├──────────┤ ├──────────┤
DATA MIRROR │ FFF │ │ DDD │ │ EEE │
└──────────┘ └──────────┘ └──────────┘
Disk 1 Disk 2 Disk 3
Figure 14. RAID-1 Enhanced, Data Strip Mirroring
Some vendors have also implemented another slight variation of RAID-1 and
refer to it as RAID-10 since it combines features of RAID-1 and RAID-0. Others
refer to this technique as RAID-6, which is the next available RAID level.
As shown in Figure 15, this solution consists of mirroring a striped (RAID-0)
configuration. In this example, a RAID-0 configuration consisting of 2 drives
(drive 1 and 2) is mirrored to drives 3 and 4.
│
┌───────┴───────┐
│ Disk │
│ Controller │
└───────┬───────┘
│
│
┌────────────┬──────┴─────┬────────────┐
│ │ │ │
┌────┴─────┐ ┌────┴─────┐ ┌────┴─────┐ ┌────┴─────┐
│ AAA │ │ BBB │ │ AAA │ │ BBB │
├──────────┤ ├──────────┤ ├──────────┤ ├──────────┤
│ CCC │ │ DDD │ │ CCC │ │ DDD │
├──────────┤ ├──────────┤ ├──────────┤ ├──────────┤
│ EEE │ │ FFF │ │ EEE │ │ FFF │
├──────────┤ ├──────────┤ ├──────────┤ ├──────────┤
│ GGG │ │ HHH │ │ GGG │ │ HHH │
└──────────┘ └──────────┘ └──────────┘ └──────────┘
Disk 1 Disk 2 Disk 3 Disk 4
Figure 15. RAID-6,10 - Mirroring of RAID 0 Drives
Performance and capacity are similar to RAID 1. 50% of total disk capacity is
usable. However, this solution always uses an
even
number of disks. RAID-1
enhanced can use an
odd
number of disks. RAID-1 also can be mixed with
others RAID levels.
26 NetWare Integration Guide