I am installing Debian 8 Jessie on a UEFI system. I have to set up RAID so I am using manual partitioning. The system installs fine in BIOS compatibility mode but there doesnt seem to be a UEFI installation option in there. Is there a non-obvious way to do that or is it not possible to do a UEFI install through the installer?
Debian 8 Jessie UEFI Installation
debian;uefi;debian installer
There are two things required to do what you want. You must boot the installer in efi mode, and you must have a efi boot partition on a gpt formatted disk for efi to boot from. The second takes more planning. for the moment let us assume you are wanting to use raid 5. I picked this one as this scenario presents every complication possible. Let's look at your options, they are external raid, raid card, and software raid.External raid is easy, it looks like a single drive, so business as usual.A raid card is complicated in that they almost never have enough documentation to have a recovery plan for a failed card other than to have a spare card. there is also the issue of drivers both for the os and for the boot, and discussions to it's value. If I was to do this I would make life simpler for myself and not boot from a hardware raid card. A couple usb sticks can be used as a software raid boot device and are cheap. See the next section for details.Software raid is my first choice for doing this, but there are some interesting details. Specifically grub only recognises raid 1, not raid 5, 6, 0, 10 or anything else interesting and the boot rom does not recognise raid at all so you need at least three partitions on each disk. You need the efi partition which must be formated fat32, the partition to put the boot raid in which will be raid 1 and formated something the bootloader can read (I like ext2 for this), and the partition for the raid 5 that you put everything else in (I like to use lvm and ext4). You can of course have more partitions. this is the minimum for this configuration. mount your boot raid as /boot and your efi partitions as /boot/efi, /boot/efi1, /boot/efi2, etc. The kernel will be installed in /boot, the grub configuration file (and whatnot) in /boot/grub and the grub core in /boot/efi/something. Then copy everything from /boot/efi to /boot/efi1 and to /boot/efi2 and any others you feel like futsing with. you can then register the additional disks as boot devices so that you can boot off any of them. the only thing you have to manually update is the additional copies of grub core should you ever upgrade to a newer version of grub. you also have to disable secure boot or find a signed copy of grub as debian does not sign grub.