On 26/01/17 05:46, Tony Mountifield wrote: > In article <1485342377.3072.6.camel at biggs.org.uk>, > Pete Biggs <pete at biggs.org.uk> wrote: >> On Tue, 2017-01-24 at 17:14 -0500, m.roth at 5-cent.us wrote: >>> So, it installed happily. >>> >>> Then wouldn't boot. No problem, I'll bring it up with pxe, then chroot and >>> grub2-install. >>> >>> Um, nope. I edited the device map from hd0 and hd1 being the RAID to >>> /dev/sda and /dev/sdb, then ran grup2-install. It now tells me can't >>> identify the filesystem on hd0, and can't perform a safety check, and >>> gives up. >>> >>> What am I missing? Google is not giving me any answers.... >>> >> Surely, if you are using software RAID, then you should configure that >> RAID in anaconda, that will then cope with setting up the partitions to >> allow booting. Basically it needs a small non-RAID partition to hold >> /boot on the boot disk. >> >> Remember that the boot sequence is generally: BIOS reads MBR and >> executes it; MBR code reads kernel from /boot and executes it (yes, >> it's more complicated than that). If the MBR code doesn't know how to >> read a RAID partition, then it's going to fail, that's why you have a >> small non-RAID partition to hold /boot. >> >> Hardware RAID is different because it interfaces at the BIOS level so >> the MBR code doesn't need to know how to specifically read it. > If you are using RAID 1 kernel mirroring, you can do that with /boot too, > and Grub finds the kernel just fine. I've done it many times: > > 1. Primary partition 1 type FD, size 200M. /dev/sda1 and /dev/sdb1. I think it wiser to have /boot at 1Gb nowadays. > 2. Create /dev/md0 as RAID 1 from /dev/sda1 and /dev/sdb1. > 3. Assign /dev/md0 to /boot, ext3 format (presumably ext4 would work too?) > 4. Make sure to setup both drives separately in grub. > > Typically I then go on to have /dev/sda2+/dev/sdb2 => /dev/md1 => swap, > and /dev/sda3+/dev/sdb3 => /dev/md2 => / > > Cheers > Tony