> [EMAIL PROTECTED] wrote: > >> >>What you are missing is that the RAID is dealing with the multiple drives >>as one drive. Two operations have to happen serially, >> > > You're kidding or vastly underestimating raid controllers. The average > db access is well served with a single block of data, stored on a single > drive. Nicely parallelizable by a raid controller if it has a minimum of > smartness. >
The data contained on a RAID is spread across all the drives in the raid, is this not true? To access data on a drive, one must get the data off all of the drives at the same time, is this not true? (yes there is flexibility with mirror and ignoring parity on reads) If you perform two different operations on the RAID, you must access each RAID drive twice. If you perform different operations on multiple different drives, you can access the same amount of data as you would with the RAID, but have parallelized operations. This is a fact. It is *the* drawback to RAID system. If you do not understand this, then you do not understand RAID systems. Perform any benchmark you want. Take any RAID system you want. Or, actually, I have a factual reason why RAID systems perform worse than multiple single drives, I have written a quick program to show it. I have even double checked on my own RAID system here. Now, your turn, show me some facts that support your position, not just that "it should." Show me how it can, show proof as to how a RAID system can be faster than its component disks. If you can't, I'm pretty sure I can safely ignore this part of the thread. ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend
