Of course, RAID levels vary a great deal in terms of their ability to handle faults
(usually meaning drive failures) and keep data availability high. The need for fault
tolerance dictates the choice of RAID level probably more than any other requirement. In
"boiled down" terms, the more redundancy in the array, the more fault tolerant
it is and the higher the availability of its data, but the way the drives are connected is
also very important. Each level has the particulars of its ability to deal with these
important reliability-related issues discussed in detail in its own section. For a more
thorough, more general look at these matters, check out the
section on reliability issues.
Note: While RAID
levels obviously vary in the degree to which they can tolerate faults, availability is
often almost as much a function of implementation as it is design. High availability in
particular is dependent upon the use of advanced features such as drive swapping and hot
spares.
Next: Degradation and Rebuilding
