Promise Technology FASTtrak100 TX User Manual page 102

Q: How does the FastTrak100 RAID controller provide storage and/or data
protection with their arrays?
A: FastTrak100 implements three different types of RAID levels as follows:
RAID 0 (stripe)
For capacity -- The FastTrak100 array will be as big as the smallest HDD in the
array times however many HDDs are in the array. Any larger HDDs will simply
be truncated. The truncated space on the bigger HDDs will then be unusable.
For sustained data transfers -- Using FastTrak100, a RAID 0 array consisting
of two HDDs will transfer at about twice the speed of the slowest HDD in the
array. A RAID 0 array consisting of four HDDs will transfer at about three times
the speed of the slowest HDD in the array.
RAID 1 (mirror)
For capacity -- The FastTrak100 array will be as big as the smallest HDD in the
array. The larger HDD will simply be truncated. The truncated space on the
bigger HDD will then be unusable.
For sustained data transfers -- The FastTrak100 array will write data at the
rate of the slowest HDD in the array. The FastTrak100 array will read data at
twice the rate of the slowest HDD in the array.
JBOD (spanning)
For capacity -- The FastTrak100 array will combine the sizes of the HDDs in the
array. As soon as one HDD is filled to capacity, the next HDD will automatically
be used.
For sustained data transfers -- There is no performance increase with
spanning (reading or writing).
FastTrak100 TX/LP™ Series User Manual
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