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

[Bart Van Assche]

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"?

More important: what will the performance impact be on SCSI devices that
do not need multipath support? UFS devices don't need multipath support
and soon (later this year) will support more than one million IOPS per
device. Further performance improvements are on the roadmap.

Thanks,

Bart.