IBM Netfinity ServeRAID-3H, Инструкция по установке и эксплуатации, Страница: 19 / 212

Enhanced RAID Level-1
When you group more than two physical drives into an array and you
select RAID level-1, the ServeRAID controller automatically assigns
the IBM Enhanced RAID level-1 to the array.
The Enhanced RAID level-1 combines mirroring with data striping.
This RAID level stripes data and copies of the data across all the
drives in the array. As with the standard RAID level-1, the data is
mirrored, and the capacity of the logical drive is 50% of the physical
capacity of the grouping of hard disk drives in the array.
The Enhanced RAID level-1 requires a minimum of three drives and,
depending upon the stripe-unit size, supports a maximum of eight or
16 drives.
The following illustration shows data arranged in an array with three
hard disk drives. The logical drive is assigned the Enhanced RAID
level-1. Notice that the first stripe is the data stripe and the second
stripe is the mirror (copy) of the first data stripe, but shifted one
drive.
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Data Stripe 1
Block 1 Block 2 Block 3
Mirror Stripe 1
Block 3 Block 1 Block 2
Data Stripe 2
Block 4 Block 5 Block 6
Mirror Stripe 2
Block 6 Block 4 Block 5
Chapter 1. Getting Started
9