HP Smart Array 6i Controller and 128MB BBWC - Manual (Page 38)

38 HP Smart Array 6i Controller User Guide
At any given RAID level, the probability of logical drive failure increases as the
number of physical drives in the logical drive increases. This is illustrated more
quantitatively in the graph ("Probability of Logical Drive Failure vs. Number of
Drives in Array" on page
38 ). The data for this graph is calculated from the
MTBF value for a typical physical drive, assuming that no online spares are
present. If an online spare is added to any of the fault-tolerant RAID
configurations, the probability of logical drive failure is further decreased.
Probability of Logical Drive Failure vs. Number of Drives in
Array
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