[dm-devel] ALUA - rescan device capacity on zero sized block devices

[Hannes Reinecke]

On 04/19/2015 12:56 AM, Christophe Varoqui wrote:
> About five years ago, we faced a somewhat simular issue with
> Symmetrix arrays, where the replicated LU of a SRDF pair (R2) was
> flagged read-only by the kernel upon discovery. Splitting the pair
> with a symcli command  made the LU read-write from the array
> controller point of view, but the Linux kernel would not promote it
> read-write dynamically.
> 
> I don't know if the Symmetrix array also use a unit attention to
> signal the change to the initiators. If it does, it might be worth
> trying to address both the 3par peer persistance and the Symmetrix
> SRDF situations.
> 
> On the other hand, if the SRDF R2 rw promotion issue has been fixed
> since, the patch might give guidance about where/how to plug the
> 3par peer persistance ghost path rescans.
> 
It's not only that; if you are faced with LUNs in standby even the
kernel wouldn't detect them properly.

I'm currently debugging this issue and will have an update soon(-ish).

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
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