PERC H965i and all Dell PERC 12 controllers are only supporting 4K sectors

[olivierlambert]

Per this discussion: https://xcp-ng.org/forum/topic/8150/sr_backend_failure_78-vdi-creation-failed-opterr-error-22

I see 2 options:

1. "Fixing" this in SMAPIv1 if it's not too complicated
2. Going faster on SMAPIv3 to at least have a working local SR driver

We are preparing an "upstream" kickoff for SMAPIv3 and the priorities, but before doing that, I wanted to get a feeling on option 1, if it's doable or not at all (ie too much efforts). What's your opinion @MarkSymsCtx ?

[olivierlambert]

Adding the Dell official doc: https://www.dell.com/support/manuals/en-us/perc-h965i-mx/perc12/virtual-disk-features?guid=guid-cd78f88c-5747-412f-8aae-6b26dd7ce2fd&lang=en-us

[olivierlambert]

Re-ping @MarkSymsCtx (adding also @edwintorok or @TimSmithCtx if Mark is away)

[edwintorok]

We're well aware of the 4K limitation and been working on it for a while. I'll let others report on the progress as I'm not directly involved in that work. Indeed doing this on SMAPIv1 is not very feasible.

[olivierlambert]

Thank you! As we told many times, we are happy to help/contribute instead of re-inventing the wheel on our side. Anything shared will be helpful to solve that more efficiently 👍

[edwintorok]

See also QubesOS/qubes-issues#4974 for some of the complexities around exposing 4K sector size to guests (although that is a different matter from supporting it on the host).
That issue mentions using losetup --sector-size to fake 512 on 4K, but I never tried whether you can then create a local SR on top of that and have everything working, but it might be a temporary workaround until we can get something better inplace.

[olivierlambert]

Thanks for the details.

So one can assume if there's no great solution for SMAPIv1, some efforts already started in SMAPIv3 internally at XenServer. Would XS storage team cooperate on this or then should we spread the effort and do the same thing on our side twice but in the open for same result? (I know it sounds as a rhetorical question but still…)