On Sat, 5 Sep 2015 20:08:05 +0100 Steve McIntyre wrote: > On Sat, Sep 05, 2015 at 07:11:44PM +0200, Francesco Poli wrote: [...] > >So, my question is: what's the recommended way to set up a RAID1 on a > >UEFI system and make sure the system will still boot, when any of the > >drives breaks? > > For actual RAID1, I'd *try* a BIOS-RAID type setup if your hardware > does it for now. Otherwise, you could try and get the multi-ESP route > working. Patches welcome if you can make it work; I'm hoping to work > on this as a feature for Stretch, but I've not found any time to start > on it yet. > > Hope this helps! Yes, it somewhat helps, thanks for your kind reply and also thanks to Stefan and Jared for their followups. So, if I understand correctly, I am basically left with two options: * enable the CSM backward compatibility mode, so that my box appears to the OS as if it were BIOS-based (assuming my box supports this mode, I haven't yet checked!) otherwise * have the box boot in UEFI mode and run the Debian Installer, create the partitions I need while setting up the software RAID1 and create two identical EFI System Partitions on the two drives; then try and help you to modify grub-efi-amd64 so that multiple ESPs are well supported Please let me understand, in case I decide to follow the second option: a) what's the recommended size for an ESP? (I found inconsistent suggestions on the web, from 1 Mibyte to 200 Mibyte!) b) my idea would be that, if the first ESP is to be mounted on /boot/efi , maybe we could mount additional ESPs on /boot/efi2 , /boot/efi3 , and so forth; at that point, whenever an upgrade of grub-efi-amd64 has to change something on the ESP mounted on /boot/efi, it should repeat the same actions on each additional ESPs mounted on /boot/efi2 , /boot/efi3 , and so forth; of course, it should check that an ESP partition is actually mounted on each mount point, before proceeding to update its content; is this feasible/reasonable? c) who is going to add the other fstab entries? should this be done manually by the user? or is there a recommended mechanism to add those entries automatically? d) there should be a debconf setting for grub-efi-amd64, where the user may choose which ESPs have to be kept updated (this is similar to the corresponding setting in grub-pc); maybe this same setting should also use efibootmgr to set the boot priorities accordingly (first the primary ESP, then the additional ones); is this possible and a good idea? e) is there anything else missing? Thanks for your time and helpfulness! -- http://www.inventati.org/frx/ There's not a second to spare! To the laboratory! ..................................................... Francesco Poli . GnuPG key fpr == CA01 1147 9CD2 EFDF FB82 3925 3E1C 27E1 1F69 BFFE
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