Promise Technology FastTRAK66, User Manual

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APPENDIX
A A
might be able to affect these assignments is to switch the PCI slot
that the card is in.
Q: How does the FastT rak/66 RAID contr oller pr ovide storage and/
or data protection with their arrays?
A: FastTrak66 implements third different types of RAID levels as follows:
RAID 0 (stripe)
For capacity -- The FastTrak/66 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 FastTrak/66, 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 FastTrak/66 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 FastTrak/66 array will write data
at the rate of the slowest HDD in the array . The FastT rak/66 array will
read data at twice the rate of the slowest HDD in the array .
JBOD (spanning)
For capacity -- The FastTrak/66 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).
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