[OmniOS-discuss] iSCSI target hang, no way to restart but server reboot

[Matej Zerovnik]

On 27. 03. 2015 16:13, Narayan Desai wrote:
> Having been on the receiving end of similar advice, it is a 
> frustrating situation to be in, since you have (and will likely 
> continue to have) the hardware in production, without much option for 
> replacement.
>
> When we had systems like this, we had a lot of success being 
> aggressive in swapping out disks that were showing signs of going bad, 
> even before critical failures occurred. Also looking at SMART 
> statistics, and aggressively replacing those as well. This made the 
> situation manageable. Basically, having sata drives in sas expanders 
> means the system is brittle, and you should treat it as such. Look for:
>  - errors in iostat -En
>  - high service times in iostat -xnz
>  - smartctl (this causes harmless sense messages when devices are 
> probed, but it is easy enough to ignore these)
>  - any errors reported out of lsiutil, showing either problems with 
> cabling/enclosures, or devices
>  - decode any sense errors reported by the lsi driver
>
> Aggressively replace devices implicated by these, and hope for the 
> best. The best may or may not be what you're hoping for, but may be 
> livable; it was for us.
>
When errors happened to you, were you able to use the pool itself and 
only iscsi target froze or did you have troubles with the pool itself as 
well...

Because on our end, when iscsi target freezes, zpool is perfectly ok. We 
can access it and use it locally, but iscsi target is frozen and can't 
be restarted.

I will check my sistem with iostat and smartctl, but we are using 
seagate drives, so some of the smartctl stats are useless on 1st sight:)

Matej