[CentOS] Help finishing off Centos 7 RAID install

Thu Jan 10 18:20:02 UTC 2019
Simon Matter <simon.matter at invoca.ch>

> It doesn't specifically.  Anaconda will create two EFI boot entries,
> each referring to one of the mirror components:
> # efibootmgr -v
> BootCurrent: 0001
> Timeout: 1 seconds
> BootOrder: 0001,0000
> Boot0000* CentOS Linux
> HD(1,GPT,534debcc-f3d6-417a-b5d4-10b4ba5c1f7d,0x800,0x5f000)/File(\EFI\CENTOS\SHIM.EFI)
> Boot0001* CentOS Linux
> HD(1,GPT,05883d1e-df21-4938-bfa1-ac11ff376572,0x800,0x5f000)/File(\EFI\CENTOS\SHIM.EFI)
> # blkid -p  -o value -s PART_ENTRY_UUID /dev/sda1
> 534debcc-f3d6-417a-b5d4-10b4ba5c1f7d
> # blkid -p  -o value -s PART_ENTRY_UUID /dev/sdb1
> 05883d1e-df21-4938-bfa1-ac11ff376572

So far my config looks similar.

>> RAID1 is going to have type FD00 (Linux RAID) whereas EFI firmware
>> expects
>> type EF00 (EFI System Partition) to boot from.
> I think you're referring to MBR partition types.  I'm not certain, but I
> don't see those values in a GPT.

No, it's GPT. What does "gdisk -l /dev/sda" show? That would be
interesting to see.

>> EFI then reads the GPT table directly and looks for a vfat filesystem to
>> boot from. Default Linux software RAID1 on EL7 uses metadata 1.2 which
>> located at the beginning of the partition. EFI won't recognize the vfat
>> filesystem behind the RAID metadata.
> Anaconda knows that it needs to use 1.0 metadata for EFI system
> partitions, which is what I mean when I said "the installer should get
> the details right."
> # df /boot/efi/
> Filesystem     1K-blocks  Used Available Use% Mounted on
> /dev/md125        194284 11300    182984   6% /boot/efi
> # mdadm --detail /dev/md125
> /dev/md125:
>             Version : 1.0

OK I see. Do you also have /boot mounted on its own MD device?

>> Maybe certain EFI firmware is more tolerant but at least in my case I
>> didn't get it to work on RAID1 at all.
>> I'd really be interested if someone got it to work, how exactly it's
>> configured. How exactly do the GPT tables look, how exactly is the RAID1
>> configured.
> It might be more useful to know if this is still a problem for you with
> the current release.  I'm not sure when support for this was added to
> Anaconda, but it was fairly recent.  You may have last tried this before
> that release.

IIRC the initial install was with 7.5.