11 Oct
2004
11 Oct
'04
2:02 p.m.
>>
>> Look at what has to happen with software raid. The software
>> has to set up twice as many DMA transfers, handle twice as
>> many interrupts, block waiting on I/O twice as many times,
>> and send double the data across the bus. I'm aghast that
>> many of the classiccmp'ers here aren't revolted by that
>> just on principle. The same mentality got us MS/Windows
>> "Oh, don't worry about the cpu cycles, it's just trivial to
>> add this little pop-up box...". Trivial adds up.
>>
Trivial does add up, but so do other things. The "correct" answer depends on
properly weighing each of the factors. For each application the weights are
going to be different (sometimes radically).
An equally valid argument is that hardware raid increates the number of
transistors involved. This will increase the chance of hardware failure.
While both of the above statements are 100% true, there is no real
meaningful conclusion to draw from them on the entire problem at hand.