[PATCH 6/8] scsi: scsi-multipath: Maintain sdev->access_state

Hannes Reinecke hare at suse.com
Tue Mar 10 06:27:09 PDT 2026


On 3/10/26 12:49, John Garry wrote:
> Now that ALUA is supported, we can maintain sdev->access_state.
> 
> However, preferred_path is still not maintained as that that is related
> to transitioning  state and we do not yet support that (for SCSI
> multipath).
> 
There is an issue with the preferred path in general, namely that it 
overlays the ALUA states (ie you can have 'acive/non-optimized' _and_
the preferred path bit set). So it only makes sense for explicit ALUA
as then the preferred path bit gives us an indicator that we might /
should switch paths.

If we restrict ourselves to implicit ALUA (which I'm advocating anyway
for scsi-multipath) the preferred path becomes rather pointless as
we cannot influence path selection at all.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare at suse.com                               +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich



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