James.Smart@xxxxxxxxxx wrote:
For SAS, looking at Christoph's code -
The target id comes from the LLDD. So either the LLDD maintains a
map of SAS port addresses to target ids, or the mapping could change,
same as FC. Christoph's argument is that FC's issue was historical.
As James and I discussed on IRC, the FC mapping issue will crop up
again, such as with SAS.
A core problem is that the SCSI layer expects to address things on a
host/channel/id/lun basis, when _that_ addressing is largely a legacy
holdover from parallel SCSI.
We need to figure out a way to move SCSI layer addressing forward, and
eliminate any need for hacks such as FC's mapping.
FC's mapping hacks exist because the SCSI layer addressing needs to be
made more flexible.
Unfortunately, as James also pointed out, changing addressing will cause
lots of churn, and potentially some breakage.
Jeff
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