Promise Technology FASTtrak100 TX User Manual page 89

Under RAID 0+1, the array maintains data integrity if any 1, 2 combination survives.
Event Failed Drives
1 A1/A2
2 B2/B1
3 A1/B2
4 B1/A2
5 A1/B1
data
6 B2/A2
data
Spanning (JBOD)
A Spanning disk array (also aptly named as JBOD for "Just a Bunch of Drives") is
equal to the sum of all drives when the drives used are of different capacities.
Spanning stores data on to a drive until it is full, then proceeds to store files onto the
next drive in the array. There are no additional performance or fault tolerance array
features in this array. When any disk member fails, the failure affects the entire array.
FastTrak100 TX/LP™ Series User Manual
Array Status
Working B1/B2 retain array integrity
Working A1/A2 retain array integrity
Working B1/A2 retain array integrity
Working A1/B2 retain array integrity
Offline
Offline
Why?
B2/A2 contain only half of array
A1/B1 contain only half of array
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