Hi, On Mon, Aug 11, 2025 at 01:36:03AM +0100, Alain D D Williams wrote: > The main disk is 2 disks in a RAID-1 pair (mirroring). The boot partition is > /dev/md0 that is built thus: > > md0 : active raid1 sda1[0] sdb1[1] > 510976 blocks super 1.2 [2/2] [UU] > > I get an error installing grub. I do not understand it let alone know how to > fix it. Note that the error happens for sda but not sdb: > > # grub-install --target=i386-pc /dev/sda > Installing for i386-pc platform. > grub-install: warning: You have a short MBR gap and use advanced > config. Please increase post-MBR gap..
I suspect you have too few sectors between the beginning of the disk and the start of sda1 for grub to fit its core.img in. Please show us the output of: # fdisk -u -l /dev/sda # fdisk -u -l /dev/sdb (both harmless / read-only) It is recommended to start partitions 1 MiB into the disk. Thanks, Andy -- https://bitfolk.com/ -- No-nonsense VPS hosting
