booting btrfs

[Chris Murphy]

On Sep 26, 2013, at 4:15 PM, Vladimir 'φ-coder/phcoder' Serbinenko 
<address@hidden> wrote:

> On 26.09.2013 22:51, Chris Murphy wrote:
>> 
>> Open question is if on BIOS hardware, if a 1MB BIOSBoot is preferred over 
>> the 64KB Btrfs bootloader pad? I don't know off hand if each member disk, or 
>> subsequently added disks, each have this 64KB pad or just the first member.
>> 
> This is besides the point. I'm fine to discuss such things but in a
> separate thread.

2nd question is whether additional things are needed for /boot on btrfs. Using 
qemu/kvm and vbox I've tested maybe 6 virtual disks using btrfs single, raid0, 
raid1, and raid10 configurations, and consistently GRUB can boot /boot as a 
subvolume. I don't know how resilient this is as the file system is used and 
chunks end up on different devices or if this is sufficiently abstracted that 
it doesn't matter and just works; including if devices are removed and added.

3rd question, related, is if it's needed and planned work for GRUB to know 
about subvolid such as (hd0,gpt5,sv218) so that it can directly locate a 
subvolume regardless if it's been moved or renamed or if the default subvolume 
has been changed.



Chris Murphy