On Wednesday, March 16, 2005, 2:05:00 PM, Goran wrote: GJ> OK that is for hardware level RAID. I had thought that you would offset GJ> the extra processing time by being able to write less to each drive.
GJ> Now does anyone know how much overhead Windows 2000/2003 software RAID 1 GJ> on dynamic disks produces over hardware level RAID 1? GJ> I am assuming it would be substantial. This is difficult to quantify, but in my limited experience the difference in load between software RAID1 and hardware RAIDx is approximately the same as the difference between using IDE drives and using SCSI drives. SW RAID1 is not hard on the CPU except that it has to coordinate the write operations etc which leads to some extra queuing work/delays. With a good hardware based RAIDx the effect is that this coordination is handed off to the controller so the CPU spends more time doing actual work and less on managing the drive subsystem. This is roughly similar to the performance gain you get by going to a decent SCSI based system since SCSI systems have higher level communications protocols that generally allow the CPU to "get on with other business" in much the same way. In the end these choices are all about how much money you have and your performance goals. _M This E-Mail came from the Message Sniffer mailing list. For information and (un)subscription instructions go to http://www.sortmonster.com/MessageSniffer/Help/Help.html
