Hi,
I'm setting up a raid 10 installation with 4 drives, using the Debian installer on a bootable usb stick. On each drive, I've got two partitions:
1 = EFI bootable system
2 = Raid
I add the Raid partitions to a Raid 10 array, then configure a logical volume group with swap and ext4 root volumes.
The installer sets everything up nicely and installs grub-efi on the first drive. When I reboot everything works as expected.
I then repeat the following for drives 2-4 (b-d) where <X> is the drive letter to install grub on each drive:
umount /boot/efi
mount /dev/sd<X>1 /boot/efi
grub-install --ef-directory=/boot/efi /dev/sd<X>
After doing the above, I wanted to check that I could boot from any drive other that the first one.
I failed drive 'a', then removed it from the raid array. I physically removed the drive and then rebooted.
The system tried to reboot, but failed because it tries to mount /dev/sda1 to /boot/efi (using the UUID of the drive).
If I edit the /etc/fstab file and comment out the line that mounts /dev/sda1 to /boot/efi, then I'm able to boot from any drive and the system appears to work normally.
My question is, does /boot/efi need to be mounted? What potential problems do I face if it isn't mounted?
I assume that kernel upgrades will still work since they are in /boot which is in the raid, the only thing under /boot/efi is the efi configuration.
Thanks!
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Raid 10 configuration, booting from any drive
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Re: Raid 10 configuration, booting from any drive
The EFI partition does not need to be mounted for normal operation. It contains the GRUB EFI core image in /boot/efi/EFI/debian/grubx64.efi (for Debian on PC with 64-bit UEFI firmware). So it only needs to be mounted when running grub-install, including when the grub-efi* packages are upgraded.
You can add the "nofail" option in the fstab line to avoid mount failure when the partition is missing. I guess the 90-second delay still happens though.
Notes :
1) For EFI targets the device argument /dev/xxx is meaningless and grub-install ignores it, so it can be omitted.
2) /boot/efi is already the default for --efi-directory, so if you mount each EFI partition on /boot/efi in turn you don't need to specify it.
You can add the "nofail" option in the fstab line to avoid mount failure when the partition is missing. I guess the 90-second delay still happens though.
Notes :
1) For EFI targets the device argument /dev/xxx is meaningless and grub-install ignores it, so it can be omitted.
2) /boot/efi is already the default for --efi-directory, so if you mount each EFI partition on /boot/efi in turn you don't need to specify it.
Re: Raid 10 configuration, booting from any drive
Great, thanks for the info!
I think I'll leave it unmounted for now.
I think I'll leave it unmounted for now.