domU freeze

[Emmanuel Dreyfus <manu%netbsd.org@localhost>]

Hello

I have the case of a domU that hangs every few hours. I am looking for
hints about how to investigate it. 

The machine is quite critical, hence I had to setup a watcher scripts
that reboots it when it stops answering pings. That makes manual inspection
difficult.

A very frustrating point: this machine has been fine for years, and it 
started crashing when I migrated it to a new dom0 (copied the kernel,
rsync the filesystem). When I experienced a few crashes, I moved it 
back to the dom0 where it worked fine, but now it keeps crashing.

dom0: NetBSD 9.2 / Xen 4.15.0
domU: NetBSD 9.0 i386 PVH+shim. It uses ipf a lot.

I thought about rebuilding with a DDB_COMMANDONENTER that tells something
(but what?), but it would not help since the machine does not panic. 
Is there a way to script a domU into DDB from the dom0?


-- 
Emmanuel Dreyfus
manu%netbsd.org@localhost