17.04.2018 21:40, Neil Rickert пишет:
On 04/17/2018 12:35 PM, Liam Proven wrote:
I guess it only needs the first 512 bytes for a boot sector, so a 2MB partition is plenty.
I think it needs more that 512 bytes. The bulk of the grub code is in "/boot/grub2/i386-pc/core.img". It needs enough to be able to locate that code.
Wrong. core.img is exactly *the* code that locates /boot/grub2 which contains bulk of grub2. It is effectively copy of what is written into bios_boot or other location where you chose to install grub2. 512 bytes sector contains code that reads core.img using absolute disk location(s).
And "btrfs" makes that more complex, because there can be multiple versions of "core.img" in different snapshots.
No. /boot/grub2/i386-pc is subvolume and so exempt from (root) snapshots. There is always only one bootloader which is overwritten on update.