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From: Zaphod Beeblebrox <zbeeble@gmail.com>
Date: Mon, 3 Jul 2017 20:32:20 -0400
Message-ID: <CACpH0McnnOzme7fJP=RvpCvorZNL2h4shW-4ML-4AXeNmks6vg@mail.gmail.com>
Subject: How to diagnose hang just before reboot...
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So... I've got an 11-STABLE machine that is ZFS only, but the march of
zeros competes and the geoms destroy themselves... then it just sits there
with that on the screen ... not rebooting.

What do I twiddle to diagnose the cause (this didn't happen before a bunch
of changes... so I'm not sure who is the culprit).