Re: Howto migrate a FreeBSD cloud instance to another one without native FreeBSD support?

Miroslav Lachman <000.fbsd@quip.cz> wrote;
> On 26/12/2023 15:22, Michael Grimm wrote:

>> Hi,
>> I do run FreeBSD 14.0-STABLE instances in OVH's public cloud for some years already. Now, I do need to migrate my FBSD instances to new instances (old ones are no longer supported).
>> In the past one could create new instances running FBSD from the start, but OVH has removed that option. I do have used Ubuntu rescue systems in the past for my FBSD instances, thus I am familiar in using Ubuntu's OpenZFS functionality.
>> Sadly, OVH doesn't offer Linux systems installed on ZFS pools. Thus I do have to stick to Linux systems without.
>> Here are my questions regarding using Linux (Ubuntu) rescue systems:
>> # What would be the closest equivalent to FBSD's gpart tool?
>> gdisk, …?
> 
>> # Would it be possible at all to go for legacy booting of FBSD?
>> gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 ada0
>> # Or, would it be better/easier to consider UEFI booting instead?
>> rsync /boot/loader.efi to rescue system
>> # Are there other promising strategies for migrating feasible?
> 
> I know nothing about OVH and almost nothing about what kind of FreeBSD setup you want to migrate (partitions, UFS vs ZFS etc.) but one thing I can imagine in you situation is creating everything from Linux rescue (partitions, formatting to UFS or ZFS, boot sector, rsync old FreeBSD instance to newly created...)

Sorry, if I haven't been clear enough:

#) I do want to migrate an existing ZFS pool (from one instance to another (zfs send | zfs receive). 
   This I have done numerous times before.

#) New to me is the preparation of the target disk out of an Ubuntu/Linux rescue system.
   Namely, how to partition with Linux functionality (gdisk, cfdisk, …) lacking gpart?
   Namely, which kind of booting to use (legacy versus EFI)?

> And the second is: you can prepare small minimalistic FreeBSD image in Bhyve / VirtualBox etc. make a copy of it with dd and then write it by dd to your new instance's disk with the help of Linux rescue system. Then you can reboot to a minimalistic FreeBSD system, enlarge partition(s), use growfs or zpool / zfs enlargement and then finally move data from the old instance to this new instance by rsync, or zfs send, or whatever tool you prefer.

Thanks for this info, very much appreciated.

Regards,
Michael