At Sun, 01 Jun 2025 07:16:18 +0700, Robert Elz <k...@munnari.oz.au> wrote: Subject: Re: Xen boot strangeness (Was: Re: [SOLVED] Re: Xen 4.18.5_20250521nb0 not ELF binary (Was: Re: EFI and Xen)) > > Date: Sat, 31 May 2025 13:24:33 -0700 > From: "Greg A. Woods" <wo...@planix.ca> > Message-ID: <m1uLSkr-00Mo5fC@more.local> > > > | though that would be secondary if there were support to configure a dump > | device after boot. FreeBSD has had a dumpon(8) utility since 2.0.5. > > Of course NetBSD can do that, see swapctl(8) -D and more commonly, the "dp" > flag (like "sw" for swap, either one, or both, can be used in a "swap" type > entry) in fstab.
Ah yes, sorry I meant to check if swapctl had a way to set dumpdev, and
I had a niggling thought it could but my sleep-deprived brain just
wanted to hit "send"....
> The only conceivable reason I can imagine for wanting to pass dumpdev
> via the boot loader would be if the kernel were crashing before getting
> init started (no chance to process fstab at all).
Indeed, but even that could be done, with about the same effectiveness,
with a "dump=" parameter on the kernel command line, and that works even
for a Xen dom0 where the boot loader can only pass such info to the
NetBSD kernel via the command line configured in /boot.cfg anyway....
While the window between where the kernel actually has enough stuff
configured to actually write a dump and where init is started is rather
small, there's considerably more going on with many user processes
starting and running between when init starts /etc/rc and when
/etc/rc.d/swap1 finally gets run where an interesting crash might be
more likely to occur.
--
Greg A. Woods <gwo...@acm.org>
Kelowna, BC +1 250 762-7675 RoboHack <wo...@robohack.ca>
Planix, Inc. <wo...@planix.com> Avoncote Farms <wo...@avoncote.ca>
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