Swapping on ZFS - stability issue

[Kris Kennaway]

Peter Schuller wrote:
> [kris]
>> Please follow the directions in the developers handbook chapter on kernel 
>> debugging to obtain the relevant debugging information.
> 
> Apologies. Aside from the first instance, where the machine had sat
> there for 12+ hours, I never got any panic message or anything like
> that which gives an opportunity for a stacktrace, etc.

Doesn't matter, you can debug deadlocks too :)

> [pjd]
>> This is a known issue also in OpenSolaris. ZFS needs to allocate memory
>> to send I/O request, and when there is no memory, it can't allocate it
>> thus can't swap a process out and free it.
> 
> Ok, so a known issue. Unless someone tells me otherwise I'll update
> the ZFS-on-FreeBSD Wiki pages to warn about this issue (assuming it's
> editable by me).

Thanks.

Kris