EFI/ZFS Update: successful tests, need more complex vdevs

[Steven Hartland]

ZFS Boot Environments (BE) support was also wired up to Beastie last 
night by Allan for those interested in that :)

On 15/01/2016 14:42, krad wrote:
> Thanks this is useful information. I did have a look at the way pc bsd 
> was using grub to boot rootonzfs systems, and they used the Kfreebsd 
> options. This looked kind of handy as you might have been able to 
> specify the zfs file system to boot off. This would be a real boost 
> the boot environments as you could easily choose which one to boot 
> into, making upgrade recovery far easier.
>
> Presumably the freebsd@ part in your setup refers to the zfs file 
> system? In which case you could have multiple menu entries with 
> different file systems specified, this is assuming the grub config is 
> on the efi disk though?
>
> I'm also curious how this would his work when the are multiple pools 
> on the same disk for some reason.
>
>
>
> On 15 January 2016 at 14:23, Eric McCorkle <eric at metricspace.net 
> <mailto:eric at metricspace.net>> wrote:
>
>     On 01/15/16 06:51, Renato Botelho wrote:
>
>             On Jan 15, 2016, at 00:41, Steven Hartland
>             <killing at multiplay.co.uk <mailto:killing at multiplay.co.uk>>
>             wrote:
>
>             Just wanted to let everyone know that I just finished
>             committing these changes to the tree.
>
>             Huge thanks to Eric's for his work on this, as well as
>             everyone else who contributed.
>
>             I've set the target for MFC of 2 weeks, so I hope to be
>             able to get this into stable/10 before the 10.3 slush, so
>             if you're interested in this change please test a head
>             build > r294068 ASAP.
>
>
>         Great work, thanks!
>
>         Is there a way to move a installed ZFS system to EFI?
>
>
>     (Refer to Steven's guide for the simple case where you can create
>     an EFI partition)
>
>
>     == Using GRUB ==
>
>     GRUB can be used with loader.efi on a ZFS system (I use this
>     myself, as I have a Gentoo install in the same ZFS volume)
>
>     Make sure you install GRUB with EFI support (the ports collection
>     will handle this).  The grub port comes with a script that
>     auto-detects filesystems and sets up a grub.cfg in /boot/grub/. 
>     However, that script won't properly detect ZFS partitions, so
>     you'll need to add it manually.  The entry is simple.
>
>     I have a zfs volume called "data", which has the freebsd system
>     root on the filesystem data/freebsd.  The GRUB entry then is:
>
>     menuentry "FreeBSD" {
>       search.fs_label data ZFS_PART
>       chainloader ($ZFS_PART)/freebsd@/boot/loader.efi
>     }
>
>     The first line searches for the volume "data" and binds its device
>     to the variable ZFS_PART.  The second specifies that the chained
>     bootloader is under the filesystem "freebsd" (the @ at the end of
>     the name denotes a filesystem, not a path), with the path
>     /boot/loader.efi
>
>
>     == Disks without enough space to make the GPT or EFI partition ==
>
>     If you have a ZFS filesystem on an MBR disk, or on a GPT disk
>     without enough space to create a workable EFI partition, you can
>     use one of ZFS's lesser-known features: zfs send/recv.
>
>     ZFS send and recv allow an entire filesystem to be serialized out
>     to a stream, and then read back in.  You can use this to dump the
>     entire filesystem out to a removable storage or an NFS mount. 
>     Then, use an install disk or memstick and repartition your drive,
>     using zfs recv to recreate the filesystem.
>
>
>     == On a Mac ==
>
>     (Note: this is based on research that is several years old at this
>     point.  Also, I never actually field tested this myself.)
>
>     Macs are wierd, due to their non-standard EFI.  The Mac EFI
>     implementation looks for an HFS+ partition, and loads the
>     "blessed" file as the EFI bootloader (this is a special
>     filesystem-level metadata unique to HFS+ filesystems).
>
>     In order to do an EFI boot on a mac, you'd need some way of
>     manufacturing an HFS+ partition containing only your bootloader,
>     with that file being "blessed".  The easiest way to do this would
>     be to use a Mac OS install to create an empty HFS+ filesystem, add
>     your boot loader, then use a shell command to "bless" it (this
>     command exists, but I don't remember what it is offhand).  It also
>     wouldn't be too hard to write a tool to create an HFS+ image from
>     a file (I have a half-written implementation of that lying around
>     somewhere).
>
>     Also note that Macs expect a 200MB EFI partition (which isn't
>     actually used for anything), and I've heard reports of the
>     firmware flaking out if it's not there.
>
>     I believe there are also GRUB and rEFIt options for Mac, if you
>     don't want to go to these lengths.
>
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