Re: SAS scsibus target numbering

[Alistair Crooks <agc%pkgsrc.org@localhost>]

On Fri, Jul 27, 2012 at 07:35:19AM +1000, matthew green wrote:
> 
> > I have a (mpt) SAS with seven discs connected.
> > The discs attach as sd0..sd6, but the SCSI target numbers are 0..5 and 7.
> > It appears to me that someone is skippig ID 6 for the controller.
> > It doesn't hurt too much, but it took me a while to find out why detaching 
> > targets 2, 3, 4 and 5 worked and 6 didn't (of course, 7 worked).
> > 
> > Is there a reason for this behaviour?
> 
> it's usual for the SCSI HBA to assign a targetID for itself.
> 
> besides having to use a different number, is there any real reason
> you want to change them?  perhaps a better solution would be to
> patch scsictl such that we can detach via autoconf name as well
> as scsi addresses.  maybe we should do this anyway..

Depending on LSI firmware (I think), the LSI may re-number disks
depending on how they present themselves, uuid, etc.  Some people like
this persistence (mainly Winders users, I imagine), it causes problems
for others.

To get around this, at work I used lsiutil to clear the NVRAM
settings.  Otherwise, switching out all the LSI-attached disks in one
of the Open Connect Appliances made the drives present themselves as
da33 to da64, rather than da1 to da32 - under FreeBSD, obviously.

Regards,
Alistair