On Nov 26, 2003, "Seth Bardash" <seth@xxxxxxxxxxxxxxxxxxxxxxx> wrote: > 1) Software RAID requires the cpu to do 2 reads/writes for each > read/write the system does. Wrong. A single read is enough. It's write that must get to all disks. And this is no different from hardware raid. > Most of our customers are using CPU cycles for file serving and > database functions and need all the performance they can get while > optimizing the RAID functions at a reasonble price. I'm told a number of the so-called hardware RAID controllers actually use the CPU for whatever it needs. Besides, it's not like setting up writes to a pair of disks is a lot of CPU work if done using DMA. Software RAID is stable, uses open formats and you can be pretty sure you can use software to fix things up or even to get to your data, even if the disk controller fails at the worst possible time and you can't find a replacement. -- Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/ Red Hat GCC Developer aoliva@{redhat.com, gcc.gnu.org} CS PhD student at IC-Unicamp oliva@{lsd.ic.unicamp.br, gnu.org} Free Software Evangelist Professional serial bug killer
