[ILUG] How do I map fibre channel to absolute /dev/sgxx

[Patrick Tuite]

On Monday 13 November 2006 19:16, Conor Wynne wrote:
> On 13/11/2006 16:29, "Patrick Tuite" <Patrick.tuite at ucd.ie> wrote:
> > Hi all
> >
> > I had a bit of a problem with a fibre channel tape library. We recently
> > moved a bunch of systems, some connected to a fibre channel switch with
> > the tape library & storage arrays and discovered when running scripts for
> > Amanda that the tape library media changer, previous mapped to /dev/sg6,
> > had changed to /dev/sg1. All the cabling was marked and reassembled
> > identically.
>
> Do you have persistent bindings set in the modules / modprobe.conf?
No. But thanks for the suggestion. I've looked into the documentation for this 
and it's exactly what needs to be configured for all the Fibre Channel cards 
in this SAN.
> Do you use powerpath or any other multipathing software?
The Tape Library and Storage Array do have multipath, but I believe also need 
to be configured correctly. I'm not sure about software for them. The systems 
are an IBM TotalStorage 4100 storage array and 3583 Library.

But your suggestion reminded me that the IBMtape module from IBM has a script 
that creates special devices /dev/IBMtape and /dev/IBMchanger0, so I think 
for the moment I can use the  /dev/IBMchanger0 in the Amanda configuration 
files and as long as the kernel doesn't change I think this will safely map 
to the media changer whatever SCSI id it gets assigned on boot.

Thanks

Patrick
>
> > I was wondering if anyone knew a quick way to map the SCSI ID for a
> > device to a particular block device id when the system boots to avoid
> > having to edit the scripts each time it may change if the systems are
> > ever restarted?
> >
> > Thanks
> >
> > Patrick
>
> Regards
> Conor.

-- 
Patrick Tuite
Research IT Support
UCD IT Services
Ext: 2037