Hi, On Thu, Aug 30, 2018 at 7:54 PM, daggs <[email protected]> wrote: > Greetings, > > I apologize if this isn't the right location to ask. as you guys wrote efi > support for linux I've thought you might be able to help me fill the gaps on > this issue. > > we have a production server with sles12 sp3 installed on it. > the partition table on the machine is this: > # fdisk -l /dev/sda > Disk /dev/sda: 223.6 GiB, 240057409536 bytes, 468862128 sectors > Units: sectors of 1 * 512 = 512 bytes > Sector size (logical/physical): 512 bytes / 4096 bytes > I/O size (minimum/optimal): 4096 bytes / 4096 bytes > Disklabel type: dos
See the Disklabel type: dos. If it shows dos, AFAICR it means it is MBR schema (and not a GPT schema) > Disk identifier: 0xf9a6b446 > > Device Boot Start End Sectors Size Id Type > /dev/sda1 * 2048 4192255 4190208 2G 83 Linux > /dev/sda2 4192256 468860927 464668672 221.6G 83 Linux > > mount output is as follows: > s2600wf-0:~ # mount | grep boot > /dev/sda2 on /boot/grub2/i386-pc type btrfs > (rw,relatime,ssd,space_cache,subvolid=260,subvol=/@/boot/grub2/i386-pc) > /dev/sda1 on /boot/efi type vfat > (rw,relatime,fmask=0002,dmask=0002,allow_utime=0020,codepage=437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro) > /dev/sda2 on /boot/grub2/x86_64-efi type btrfs > (rw,relatime,ssd,space_cache,subvolid=261,subvol=/@/boot/grub2/x86_64-efi) May be you should try 'gdisk' instead to list the GPT partitions in addition to the MBR ones. Following is an output from my Fedora28 EFI machine: $ sudo gdisk -l /dev/sda GPT fdisk (gdisk) version 1.0.4 Partition table scan: MBR: protective BSD: not present APM: not present GPT: present Found valid GPT with protective MBR; using GPT. Disk /dev/sda: 1953525168 sectors, 931.5 GiB Model: TOSHIBA DT01ACA1 Sector size (logical/physical): 512/4096 bytes Disk identifier (GUID): E01AB4D7-2DA7-4300-9CE8-FD573801C1DC Partition table holds up to 128 entries Main partition table begins at sector 2 and ends at sector 33 First usable sector is 34, last usable sector is 1953525134 Partitions will be aligned on 2048-sector boundaries Total free space is 3437 sectors (1.7 MiB) Number Start (sector) End (sector) Size Code Name 1 2048 411647 200.0 MiB EF00 EFI System Partition 2 411648 2508799 1024.0 MiB 8300 3 2508800 1953523711 930.3 GiB 8E00 Looking at the output you can make out the 'EFI System Partition' entry. Also if you see something like: *************************************************************** Found invalid GPT and valid MBR; converting MBR to GPT format in memory. *************************************************************** then you have a MBR style disk.. > and here is the content of /sys/firmware/efi/: > s2600wf-0:~ # ll /sys/firmware/efi/ > total 0 > -r--r--r-- 1 root root 4096 Aug 29 03:19 config_table > drwxr-xr-x 2 root root 0 Aug 29 03:17 efivars > -r--r--r-- 1 root root 4096 Aug 29 03:19 fw_platform_size > -r--r--r-- 1 root root 4096 Aug 29 03:19 fw_vendor > -r--r--r-- 1 root root 4096 Aug 29 03:19 runtime > drwxr-xr-x 11 root root 0 Aug 29 03:19 runtime-map > -r-------- 1 root root 4096 Aug 29 03:17 systab > drwxr-xr-x 140 root root 0 Aug 29 03:19 vars > > afaik, if the partition table is mbr, then for efi to boot, the boot > partition must be of type EF. in this case it isn't so I was wondering how > the system boots in efi? how does the bios detects it? > am I missing something? It depends on the BIOS on your machine. Please see <https://en.wikipedia.org/wiki/Unified_Extensible_Firmware_Interface#UEFI_booting> for details. Thanks, Bhupesh
