Re: Switch from legacy ata(4) to CAM-based ATA

On Wed, 20.04.2011 at 12:57:47 +0300, Alexander Motin wrote:
> Hi.
> 
> With 9.0 release approaching quickly, I believe it the best time now to
> manage migration from legacy ata(4) ATA to the new CAM-based one. New
> ATA code present in the tree for more then a year now, used by many
> people and proved it's superior functionality and reliability. The only
> major issue with it now is the migration process. Sooner or later we
> have to pass it, but due to major UI and API changes we can't do it
> after 9.0 release. So I propose to do it the next Sunday (April 24) to
> have as much time for troubleshooting as possible.
> 
> I have prepared the following patch to do it:
> http://people.freebsd.org/~mav/ata_switch.patch
> 
> I haven't added geom_raid to the kernel configurations because we have
> no other GEOM classes there. But tell me if you thing I should.
> 
> If somebody has any problems with new ATA stack, please repeat your
> tests with latest HEAD code and contact me if problem is still there.
> Next three weeks before BSDCan I am going to dedicate to fixing possibly
> remaining issues.

Can we then please get the "ad" device prefix back? I seem to remember
that when they were introduced they were thought to be a temporary thing
...

Unless both stacks can run in parallel, I don't see a problem with
having them both show up as /dev/ad0, etc. People with problems must
send in a complete dmesg anyway, so it should be clear what stack they
are running. The POLA violation for people upgrading from 8.x to 9.0
however is pretty big ... and unnecessary.

Cheers,
Uli