On Thu, 9 Aug 2007, Neal Becker wrote:
Bruno Wolff III wrote:
What are you going to be doing that makes you think raid 0 is desirable?
For modern home machines with lots of memory, this probably isn't going to
give you much of a speed up in typical use. It will make the chances of
your file system being lost because of a hardware problem, about double.
Raid 1 or 10 seem to be more useful for home users, than raid 0.
No! If the prob of failure during an interval T is pf, the prob of failure
for an array of 2 drives during T is 1 - (1-pf)^2.
Which, for probabilities typical of hard drives, is *very* close to twice
the probability of a single drive failure. Do the actual math. Even at 10%
failure rates (!!!!) the difference between 2X (20%) and 1 - (1-pf)^2
(19%) is insignificant for all practical purposes. You won't reach
probabilities high enough to care about the difference before the drives
are obsolete and replaced anyway.
--
Benjamin Franz
"It is moronic to predict without first establishing an error rate
for a prediction and keeping track of one’s past record of accuracy."
-- Nassim Nicholas Taleb, Fooled By Randomness
