EFI/ZFS Update: successful tests, need more complex vdevs
Karl Denninger
karl at denninger.net
Fri Jan 15 15:02:27 UTC 2016
THAT's useful around here :-)
On 1/15/2016 08:48, Steven Hartland wrote:
> 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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>>
>
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--
Karl Denninger
karl at denninger.net <mailto:karl at denninger.net>
/The Market Ticker/
/[S/MIME encrypted email preferred]/
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