Re: CAM timeouts on boot (13.0-p8, Dell R730xd, mrsas controller)

From: Warner Losh <>
Date: Fri, 01 Apr 2022 03:24:28 UTC
On Thu, Mar 31, 2022 at 9:14 PM George Michaelson <> wrote:

> I upgraded 12.2 to 13.0-p8 and hit a delay with SCSI drive
> initialisation, it loops for a timeout over the "Waiting for CAM"
> message, then proceeds.


> This interferes with the ZFS initialisation and the non-root zpool are
> not imported.

It does not. The Waiting for CAM happens before mountroot, and zpool
imports are after that.
It cannot interfere. IT's just a message that says CAM hasn't finished
probing its buses to
release mountroot. Something else must be going on.

> I intruded a  /usr/local/etc/rc.d script PROCEED: var REQUIRE: zfs
> which put it right after zfs initialisation, before any daemons, and I
> can manually zpool import the tank once the SCSI stuff has settled
> down.
> Adding delay to loader.conf CAM initialisation didn't fix this.
> There are references to this in 2018-2020 timeframe, but mostly it's
> people on desktops. I am not used to Dell rackmounts going this bad.

A dmesg would help. Generally, CAM probes all buses to completion before it
the hold on mountroot.
Something else is afoot.

My spidy sense says the kernel doesn't have all the disk controllers in it,
some are
loaded by devmatch, which happens late enough to explain the behavior you
seeing. Or maybe there's a USB device which shows up late, since I've seen
arrive too late to hold off mountroot. If adding delay doesn't help, then
that tells me
that the disk controller SIM isn't present before mountroot.