On 15. Feb 2024, at 09:38, Carsten Grzemba via illumos-developer <developer@lists.illumos.org> wrote:

If it again the  case try to force a crash dump on shutdown, e.g.
add /etc/system:

set pcplusmp:apic_panic_on_nmi = 1

then if the system is frozen
$ ipmitool -Ilanplus -U idrac-user -P password -H idrac-ip power diag

Note that you probably won't have any luck with a crash dump if the dump device is controlled by lmrc (if lmrc is the reason for frozen system)

long text:
https://illumos.org/docs/user-guide/debug-systems/#gathering-information-from-a-running-system-using-only-nmi-x86

in such case it is good idea to boot as:

ok set nmi=kmdb
ok boot -k 
or 
ok boot -kd

this way your nmi will get you to the kmdb.

And yes, we should document the ‘nmi’ property, it can have values ‘ignore’, ‘panic’ and ‘kmdb’, see https://src.illumos.org/source/xref/illumos-gate/usr/src/uts/i86pc/os/mlsetup.c?r=d32f26ee#159

rgds,
toomas