ZFS stalled after some mirror disks were lost

[Ben RUBSON]

On 13 Oct 2017 18:58, Ben RUBSON wrote:

> The issue only happens when I disconnect iSCSI drives, it does not occurs  
> suddenly by itself.
> So I would say the issue is on FreeBSD side, not network hardware :)
>
> 2 distinct behaviours/issues :
> - 1 : when I disconnect iSCSI drives from the server running the pool  
> (iscsictl -Ra), some iSCSI drives remain on the system, leaving ZFS  
> stalled ;
> - 2 : when I disconnect iSCSI drives from the target (shut NIC down /  
> shutdown ctld), server running the pool sometimes panics (traces in my  
> previous mail, 06/10).
>

> (...)
>
> Andriy, who took many debug traces from my system, managed to reproduce  
> the first issue locally, using a 3-way ZFS mirror with one local disk  
> plus two iSCSI disks.
> Sounds like there is a deadlock issue on iSCSI initiator side.

So, Andriy proposed a patch which solves this first issue :
https://reviews.freebsd.org/D12652

> Regarding the second issue, I'm not able to reproduce it if I don't use  
> geom-labels.
> There may then be an issue on geom-label side (which could then also  
> affect fully-local ZFS pools using geom-labels).

and another one for the second issue :
https://reviews.freebsd.org/D12809

Many thanks to the list, to Andriy for his nice & impressive work,  
Alexander & Edward for their reviews.

Ben