ZFS stalled after some mirror disks were lost

[Steven Hartland]

On 03/10/2017 07:12, Andriy Gapon wrote:
> On 02/10/2017 21:12, Ben RUBSON wrote:
>> A sustained read throughput of 180 MB/s, 45 MB/s on each iscsi disk
>> according to "zpool iostat", nothing on local disks (strange but I
>> noticed that IOs always prefer iscsi disks to local disks).
> Are your local disks SSD or HDD?
> Could it be that iSCSI disks appear to be faster than the local disks to the
> smart ZFS mirror code?
>
> Steve, what do you think?
Yes that quite possible, the mirror balancing uses the queue depth + 
rotating bias to determine the load of the disk so if your iSCSI host is 
processing well and / or is reporting non-rotating vs rotating for the 
local disks it could well be the mirror is preferring reads from the the 
less loaded iSCSI devices.

     Regards
     Steve