On Sat, Apr 07, 2007 at 12:40:35PM -0700, Bill Stouder-Studenmund wrote:
> [...]
> > In kernel, there's a pseudo-device (bio) to which RAID controllers registers
> > (note that we can use the controllers without bio(4) in the kernel).
> > This pseudo-device keeps a list of raid controllers, and dispatch the
> > IOCTLs. This avoids having one major device per controller driver type.
> 
> I like the idea. My concern is that we already have the ld driver 
> framework for the devices on RAID cards and this would be a separate 
> framework for the cards. Is there some way we could harmonize all of it? I 
> agree that ld devices alone aren't what you want for this as you have to 
> be able to go from having no ld's on a card to having an ld.

Not all raid card present disks though ld; some of them can also present
sd devices (either in pass-though mode, or because the interface presented
by the firmware is close to SCSI). I think it's better to separate
management of the controllers from disk operations on the logical volumes.
Maybe bio isn't a great name for what it does, but if we adopt the interface
I think we should keep the name.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--