[Lsf-pc] [LSF/MM/BPF TOPIC] Native SCSI multipath support

[Hannes Reinecke]

On 2/18/26 03:39, Martin K. Petersen wrote:
> 
> Keith,
> 
>> For nvme, we can detect if a device is multipath capable.
> 
> Yep. Same with SCSI...
> 
And that's how we handle things currently. We've learned from long and 
painful experiences that there is _NO_ way to automatically figure out
if a device is multipathed. That will always be an admin decision, so
there needs to be an opt-in mechanism.
And that needs to be set _prior_ to probing.
And you need a driver-specific opt-out, to disable all devices from
this driver for multipathing (UFS, USB, ATA, you name it).

Once you have that you can declare all ALUA capable devices with
a VPD page 83 device identifier as multipathed. Irrespective of
how many paths will show up.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare at suse.de                                +49 911 74053 688
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