Re: How to improve db performance with $7K?

Hi,

At 18:56 18/04/2005, Alex Turner wrote:
>All drives are required to fill every request in all RAID levels

No, this is definitely wrong. In many cases, most drives don't actually
have the data requested, how could they handle the request?

When reading one random sector, only *one* drive out of N is ever used to
service any given request, be it RAID 0, 1, 0+1, 1+0 or 5.

When writing:
- in RAID 0, 1 drive
- in RAID 1, RAID 0+1 or 1+0, 2 drives
- in RAID 5, you need to read on all drives and write on 2.

Otherwise, what would be the point of RAID 0, 0+1 or 1+0?

Jacques.