[LSF/MM/BPF TOPIC] Native SCSI multipath support

[John Garry]

On 17/02/2026 19:33, Bart Van Assche wrote:
> On 2/13/26 6:19 AM, John Garry wrote:
>> At ALPSS 25 I presented a proposal for Native SCSI multipath support. 
>> Let's discuss this topic at LSFMM.
>>
>> The idea for this is that SCSI could natively support multipath, like 
>> how NVMe host driver does today. It is intended as an alternative to 
>> dm- multipath support.
>>
>> I have been working on the implementation and I plan to post patches 
>> in the next cycle. I am looking at a 3-stage approach:
>> a. create a driver-agnostic multipath library, very heavily based on 
>> NVMe host multipath support.
>> The library would support features such as path management, path 
>> selection/iopolicy, failover recovery, PR, delayed removal, gendisk 
>> management etc.
>> b. switch NVMe over to use this library
>> c. add native SCSI multipath support based on this common library
> 
> A minor comment: maybe "in-kernel" makes more clear what this proposal
> is about than "native"?

dm-multipath is also in-kernel. It just requires userspace for 
config/control.

The key difference is that "native" scsi multipathing provides a scsi 
disk which supports multipathing.