Solved?: Re: Upgrade of RELENG_8 ZFS boot pool leads to unbootable system

[Paul Mather]

On Jan 2, 2013, at 2:10 PM, Matthew Seaman <m.seaman at infracaninophile.co.uk> wrote:

> On 02/01/2013 17:49, Paul Mather wrote:
>> Yesterday, I updated my RELENG_8 ZFS-only system that has worked like a champ for ages.  After a successful install{kernel,world} and reboot, I noticed the 20121130 entry in /usr/src/UPDATING and upgraded my ZFS pool via "zfs upgrade -a".  I also upgraded my boot blocks as requested, and as per the "ZFS notes" section of /usr/src/UPDATING.
>> 
>> Unfortunately rebooting with the upgraded pool failed.  The "windmill" boot spinner spins for a tiny amount of time and then stops dead. :-(  I don't get to the boot loader menu at all.
>> 
>> I downloaded a very recent RELENG_8 snapshot (FreeBSD-8.3-RELENG_8-r244923-JPSNAP-amd64-amd64-memstick.img) from pub.allbsd.org and was able to boot successfully from USB using that.  I entered Fixit Mode and tried to write the boot blocks on the memstick image onto my hard drives but the resultant system still wouldn't boot.  The commands I used (from Fixit Mode) are these:
>> 
>> 	gpart bootcode -b /dist/boot/pmbr -p /dist/boot/gptzfsboot -i 1 ad4
>> 	gpart bootcode -b /dist/boot/pmbr -p /dist/boot/gptzfsboot -i 1 ad6
>> 
>> (ad4 and ad6 are my two hard drives.)
>> 
>> If I "load zfs" before booting the USB memstick then I can see my old pool listed when I do "zfs import".  I haven't tried importing the pool because I'm not sure if that would make the problem worse.
>> 
>> Does anyone have any advice in restoring this system to bootability?  I followed the standard "root on ZFS" recipe using a two drive mirror when installing the system initially.  Each drive uses GPT with three partitions: freebsd-boot, freebsd-swap, and freebsd-zfs in that order.  Like I said at the start, all this worked for a long time until just now when I upgraded the pool to enable "feature flags" support. :-(
>> 
>> Any help is appreciated.
> 
> I think you may be running into problems with zpool.cache.  This has
> been fixed in current, which now has the ability to find the root zpool
> without a valid zpool.cache, but that I suspect is faint comfort for you.


It turns out it was my /boot.config that was preventing booting.  The system is usually always headless, so I have "-S115200 -Dh" as the sole line in /boot.config to enable a 115200 baud serial console.  This has been working fine for me up until I did a {build,install} {kernel,world} on 1st January 2013.  I was pretty sure my woes began after I did the "zpool upgrade -a" and subsequently rebooted again, but now I can't be sure whether I successfully rebooted at all after the "make installworld" and mergemaster step.

Does anyone know a sure-fire way of getting a dual console setup (high-speed serial + VGA).  The recipe I had been using had worked well for a long time.  I had "-S115200 -Dh" in /boot.config and the following entries in /boot/loader.conf:

	boot_multicons="YES"
	comconsole_speed="115200"
	console="comconsole,vidconsole"

Now, though, if I have "-S115200 -Dh" then the system locks up at boot.  Removing /boot.config gets me dual console, but only at 9600 baud. :-(

Cheers,

Paul.

PS: Is the BOOT_COMCONSOLE_SPEED entry in /etc/make.conf needed?  I was under the impression it has been obsolete for a while and took it out of my /etc/make.conf file.