IBM ServeRAID, User Reference

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Create an array using the physical drives.
Then create a logical drive within that array.
The data is striped across the drives, creating
blocks.
Notice that the stripe labeled * is the data
stripe and the stripe labeled ** is the copy of
the preceding data stripe. Also, notice that
each block on the mirror stripe is shifted one
drive.
1 2
6
3
5
4
1
4 6
5
3
2
*
*
**
**
With RAID level-1E, if one of the physical drives fails, the ServeRAID controller
switches read and write requests to the remaining functional drives in the RAID
level-1E array.
RAID level-1E offers the following advantages and disadvantages:
Advantages Disadvantages
v 100% data redundancy
v High performance
Allows only 50% of the physical drive
storage capacity to be used
Understanding RAID level-5
RAID level-5 stripes data and parity across all drives in the array.
RAID level-5 offers both data protection and increased throughput. When you
assign RAID level-5 to an array, the capacity of the array is reduced by the capacity
of one drive (for data-parity storage). RAID level-5 gives you higher capacity than
RAID level-1, but RAID level-1 offers better performance.
RAID level-5 requires a minimum of three drives and, depending upon the level of
firmware and the stripe-unit size, supports a maximum of 8 or 16 drives.
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IBM ServeRAID: User’s Reference, Version 5.10