On 26/01/17 05:46, Tony Mountifield wrote:
In article <1485342377.3072.6.ca...@biggs.org.uk>,
Pete Biggs <p...@biggs.org.uk> wrote:
On Tue, 2017-01-24 at 17:14 -0500, m.r...@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
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