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SuperTrak66™ User's Manual
6.4
Configuration Ideas
This part of the chapter covers additional ideas which are helpful to bear in mind
while considering RAID configurations.
Fault Tolerance
Hard drives aren't the only things that can fail in a server room full of equipment,
PCs, hard drives, cables, connections, and power supplies. There are literally
hundreds of things that could go wrong on any given day. Although this is a
disturbing thought that has led some to seriously question their career in
computers and networking, there are some additional ways to prevent a server's
RAID storage downtime and perhaps extend one's livelihood.
Since SuperTrak66 maintains four independent data channels and assigns just one
drive per channel, users are protected in case a single drive OR an entire data
channel fails. This provides an added level of protection than other RAID controllers
that allow connecting two (more) drives to the same channel connector.
Hot Spare Drive(s)
A good precaution to protecting your array integrity in the event of drive failure is
maintaining a hot spare drive. A hot spare is a drive which is connected to the array
system, but is not assigned as a member of the array. In the event of the failure of
a drive within a functioning fault tolerant array, the hot spare is activated as a
member of the array. The spare drive effectively takes the place of the failed drive
and the RAID system immediately begins to rebuild data on the drive. When the
rebuild is complete, the array is returned to fault tolerant status. Once the failed
drive is replaced, the new drive is automatically recognized as a hot spare in the
event of a subsequent drive fault.
Some possibilities for making use of hot spares can include:
A 2-drive mirrored array with 2 hot spare drives. This allows for triple drive
fault tolerance before the array would be set offline.
A 3 -drive RAID 3 array with 1 hot spare for double fault tolerance under
RAID 3.
A 3 -drive RAID 5 array with 1 hot spare for double fault tolerance under
RAID 5.
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Chapter 6
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