Re: Switchover to CAM ATA?

On Apr 27, 2010, at 5:33 AM, Gavin Atkinson wrote:

> On Mon, 2010-04-26 at 10:33 -0600, M. Warner Losh wrote:
>> My opinion for the path forward:
>> (1) Send a big heads up about the future of ataraid(5).  It will be
>>    shot in the head soon, to be replaced be a bunch of geom classes
>>    for each different container format.  At least that seems to be
>>    the rough consensus I've seen so far.  We need worker bees to do
>>    many of these classes, although much can be mined from the ataraid
>>    code today.
> 
> Losing ataraid would be bad.  I suspect there are a lot of installs
> using it - especially as there is no way to create any other mirror from
> sysinstall.  However, I'm not actually sure that the functionality it
> provides is easy to push down into GEOM.
> 
> ataraid depends on knowing a lot about the underlying hardware, in order
> to know which format of metadata to use.  i.e. it needs to know that the
> disks are attached to (say) a Highpoint controller.

This is unfortunately true, especially on older controllers.  I think that there
are reasonable ways to address this though, by having CAM SIMs provide a
bit more information in their PATH_INQ response.

Scott