This diskfailure should not panic a system, but just disconnect disk from ZFS

[Willem Jan Withagen]

On 21-6-2015 23:01, Bob Friesenhahn wrote:
> On Sat, 20 Jun 2015, Steve Wills wrote:
>>> rev=0x00 hdr=0x00
>>>     vendor     = 'Areca Technology Corp.'
>>>     device     = 'ARC-1120 8-Port PCI-X to SATA RAID Controller'
>>>     class      = mass storage
>>>     subclass   = RAID
>>
>> You may be hitting the zfs deadman panic, which is triggered when the
>> controller hangs. This can in some cases be caused by disks that die
>> in unusual
>> ways.
>
> Notice that the RAID controller is a PCI-X device (shared parallel, not
> dedicated serial like PCIe).  The whole PCI backplane could have hung.

I had this panic problem a while ago, but since then it has sort of 
recured quite a few times....

However this times I was working on the system and noticed it right 
away. So I just went into the basement and chekced the box.

Console is not really dead:
  - I can switch terminals
      but cannot login
  - I can ping
      but cannot ssh into it.
  - Can not break into the kernel
There is totally no I/O shown of the disk. No of the leds flash for lile 
atleast 30 sec...

Just the reset button get me back to normal...

So that suggest a lot more that something is really hung.

Question is how can I debug this? Breaking into the kernel (ctl-del-esc) 
does not seem to work...

Also contemplating to get an Areca controller for PCIe instead but that 
is shelling out again another $250. And that just to get JBODs

--WjW