suspend/resume versus OpenZFS on USB

[Graham Perrin]

On 05/09/2020 18:18, Graham Perrin wrote:
> On 05/09/2020 10:26, Hans Petter Selasky wrote:
>> On 2020-09-05 11:00, Graham Perrin wrote:
>>> On 04/09/2020 09:01, Hans Petter Selasky wrote:
>>>> On 2020-09-04 01:42, Graham Perrin wrote:
>>>>> This week for the first time I toyed with OpenZFS on a USB device: 
>>>>> a mobile hard disk drive connected to the dock of an HP EliteBook 
>>>>> 8570p.
>>>>>
>>>>> A light test, with the pool imported but not writing to the 
>>>>> dataset at suspend time.
>>>>>
>>>>> At resume time (22:31), the device was still physically connected 
>>>>> but the pool suffered an I/O failure (and the keyboard and 
>>>>> trackball on USB were unusable).
>>> …
>>>> We need output from "procstat -akk" to see where ZFS/USB is hanging.
>>>>
>>>> --HPS
>>>
>>> For test purposes I reproduced the behaviour with a different 
>>> device, a USB flash drive (connected to the same dock).
>>>
>>> Attached:
>>>
>>> 2020-09-05 09:27:55 procstat -akk.txt
>>>
>>> – output from procstat -akk
>>>
>>> 2020-09-05 09:17:59 suspend 09:26:49 resume.txt
>>>
>>> – the output in context.
>>>
>>> Thank you
>>>
>>> Graham
>>>
>>>
>>
>> Hi,
>>
>> USB is not hanging.
>>
>> It looks like a problem with USB resume, that no devices are 
>> recognized, until you re-plug them ...
>>
>> --HPS
>
> Hi
>
> If I export the pool before suspend, no problem at resume time.
>
> …

Please

Is there any way to avoid the need to export before suspending the 
computer?

Might there be a future improvement to support for USB?

Thanks