Re: RAIDframe: passing component capabilities

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

> given that RAIDframe (nor ccd, nor much else) has a general 'query the
> underlying layers to ask about this capability' function.
Is there a ``neither'' missing between ``that'' and ``RAIDframe''?

> (NetBSD 8 refusing to configure a RAID set because of this is not an
> option.)
Of course not. With my model, you would need to (re-)configure the RAID set 
with ``all components have SCSI tagged queueing'' in order for the RAID 
device to announce that capability. If one of the drives is SATA, that 
configuration fails. If you later try to replace a SCSI drive with a SATA 
one it fails like it fails when the replacement drive has insufficient
capacity.
It's just like with capacities: There's no need to announce the full component 
capacity to the set (well, in fact, you don't use the full drive capacity for 
the partition that constitutes the component), but the component needs to have
at least the announced capacity (in fact, you need to be able to create a 
partition of sufficient size on the drive).
With capabilities, there would also be no need to announce all the drive's 
capabilities, but a component (original or replacement) needs to have at least
the announced capabilities.