Re: ZFS on root - almost there

[Chavdar Ivanov <ci4ic4%gmail.com@localhost>]

On Sat, 22 Feb 2020 at 11:27, Roy Marples <roy%marples.name@localhost> wrote:
>
> On 14/02/2020 12:58, Roy Marples wrote:
> > So I thought I would have a go at setting up ZFS on root.
>
> I've now comitted enough to manually build a ramdisk to set this all up.
> Quick instruction steps which I'll document on web page later:
>
> Compile the ramdisk
> cd src/distrib/amd64/ramdisks/ramdisk-zfsroot
> nbmake-amd64
>
> Ensure you are using GPT and not MBR. If you need to change, dd the disk
> using /dev/zero as source for about 32k and then the installer will ask you if
> you want MBR or GPT. Once set, it will not prompt to change it again.
>
> Use the installer to do a normal installation, extracting base, modules and
> rescue sets to a small FFS parition (I chose 2G). Do not allow the installer to
> use the rest of the disk.
> Drop to the prompt and copy the ramdisk you made earlier to /
> Edit /boot.cfg and add this menu item:
> menu=Boot ZFS root:fs /ramdisk-zfsroot.fs;boot
>
> Create a ZFS pool on another partition called rpool.
> Create the ZFS root filesytem called rpool/ROOT.
> zfs set mountpoint=legacy rpool/ROOT
> This step is important - the only downside is if you want to create any ZFS
> datasets in rpool/ROOT you need to either set mountpoints in /etc/fstab or
> specify them as they will automatically inherit legacy from ROOT.
> Extract the sets you want rpool/ROOT.
> Create dev on rpool/ROOT, copy MAKEDEV from /dev to it, cd to it and run
> ./MAKEDEV all
> Copy your /etc/fstab to rpool/ROOT/etc, but remove the / entry.
> Ensure that rc.conf is setup in rpool/ROOT/etc and it has zfs=YES
>
> You should now be good to go!

Surely I have missed and/or misuderstood some of the above, but I am getting:
...
Starting ZFS on root boot strapper
Copying needed kernel modules from NAME=boot:/stand/amd64/9.99.47/modules
mount: no match for 'boot': No such process
/mnt//stand/amd64/9.99.47/modules/zfs/solaris.kmod not found!
/mnt//stand/amd64/9.99.47/modules/zfs/zfs.kmod not found!
umount: /mnt: not currently mounted

Importing rpool, mounting and pivoting
internal error: failed to initialize ZFS library
....

It seems it tries to mount the small ufs root on /mnt using
'NAME=boot' label, but the label created by the standard installed is
some GUID.



>
> WARNING: There seems to be a bug that once booted into a ZFS root and mount any
> device and write to it the system will hang trying to unmount it. This is not a
> fault with the ramdisk, but rather with how ZFS works with device nodes on ZFS.
> So to update the kernel, boot into the FFS partition and copy from the ZFS
> partition rather from doing it within the ZFS root.
>
> Once that is fixed I might look into trying to automate some of this in our
> installer.
>
> Good luck!
>
> Roy



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