Date: Sat, 8 Jan 2011 18:09:27 -0800 (PST) From: Nick Sayer <nsayer@kfu.com> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/153804: boot from zfs kernel.old recovery undocumented/impossible Message-ID: <201101090209.p0929Ref003109@quack.kfu.com> Resent-Message-ID: <201101090210.p092A4Sh008047@freefall.freebsd.org>
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>Number: 153804 >Category: kern >Synopsis: boot from zfs kernel.old recovery undocumented/impossible >Confidential: no >Severity: critical >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: doc-bug >Submitter-Id: current-users >Arrival-Date: Sun Jan 09 02:10:04 UTC 2011 >Closed-Date: >Last-Modified: >Originator: Nick Sayer >Release: FreeBSD 8.2-RC1 amd64 >Organization: Just me >Environment: System: FreeBSD quack.kfu.com 8.2-RC1 FreeBSD 8.2-RC1 #5: Sat Jan 8 16:14:48 PST 2011 root@quack.kfu.com:/usr/obj/usr/src/sys/QUACK amd64 Disk configured for gptzfsboot, root on ZFS >Description: After creating an unbootable kernel, the steps necessary to boot kernel.old are unclear. The problem is that under normal circumstances, /boot/zfs/zpool.cache is loaded in some magic way - this is evidenced by breaking into the loader (by pressing "6") and doing an lsmod. If you attempt to unload, then manually load kernel and zfs.ko, the zpool.cache file is not loaded. Attempting to load zpool.cache with the load command fails, and there is no alternative command to do so. Attempting to boot the kernel without the zpool.cache loaded results in an irrecoverable failure to mount root. >How-To-Repeat: Set up a zfsroot system. boot. hit '6' at the loader menu, then "unload", "load kernel" and "load zfs.ko", then "boot". >Fix: Either loading zfs.ko needs to perform whatever magic is necessary to fetch zpool.cache, or a command needs to be added (like load_geli) to fetch the zpool cache. >Release-Note: >Audit-Trail: >Unformatted:
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