User`s manual

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Frequently Asked Questions
This section lists frequently asked questions involving pre-installation, drive issues,
installation, and post-installation.
Pre-Installation
(Speed, Device Types, Capacity, Cabling)
Q: What kind of hard drives can I use for creating an array?
A: You can use any IDE/EIDE hard drive(s) to create arrays. You should use matching
drives for multiple-drive arrays to maximize capacity usage as well as performance.
Ultra ATA/133 drives are recommended for highest performance.
Q: Can I use ATAPI devices on the array?
A: No. There is no driver layer that will support ATAPI packet messages.
Q: How does the Promise controller provide storage and/or data protection with their
arrays?
A: The controller implements three different types of RAID levels as follows:
RAID 0 (stripe)
For capacity - The array will be as big as the smallest HDD in the array times the
number of HDDs that 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 - 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 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 array will write data at the rate of the slowest HDD
in the array and will read data at twice the rate of the slowest HDD in the array.
Drive Issues
Q: Can I add a drive to a RAID array via hot-swap and dynamically adjust the array
size/configuration?
A: No. The system does not support dynamically adjustable RAID size/configurations.
Q: Do the HDDs have to be the same size?
A: The HDDs that you use do not have to be the same size. If the sizes differ, the system
will “adjust” the HDDs so that they are compatible. Basically, it will truncate the bigger
HDD so the sizes match. Any unused space that results from this is unusable, so don’t
use HDDs that differ too much. It’ll work, but it’s a waste.