Re: Raw Devices: Increased Performance?

In article <EiAXoAAcT$8xEwOu_at_smooth1.demon.co.uk>, David Williams <djw_at_smooth1.demon.co.uk> wrote:

> Generally disk drive controllers themselves which have the elevator
> seek algorithm built-in to them, also the database engine has this
> built-in as well. Why waste time doing it an extra time ?

Good point. If I remember right, the Oracle kernel has an elevator algorithm built in, and it was useful when disk controllers weren't doing the job. Nowadays, it doesn't make a lot of sense for the kernel to sort the blocks going to individual drives since the disk controller can do a better job of it. The controller knows where the head really is and sees all the traffic going to the drive, not just dbwr's writes. I believe most Oracle ports now have that Oracle elevator algorithm turned off.

FWIW. -Jef Received on Wed Jul 24 1996 - 00:00:00 CEST