Similar to https://bugzilla.redhat.com/show_bug.cgi?id=1652806, the upgrade failed with a very quick error like error: file '/grub2/grubenv' not found
e, I couldn't capture it but the server just kept rebooting over and over.

I posted a discussion on the new discourse at https://ask.fedoraproject.org/t/error-no-such-device-after-fedora-30-upgrade-on-software-raid/2051 and have yet to receive any replies.

Here's an fdisk and lsblk:

Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 524288 bytes / 1048576 bytes


 lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE   MOUNTPOINT
loop0         7:0    0   1.6G  1 loop   
loop1         7:1    0   6.5G  1 loop   
├─live-rw   253:0    0   6.5G  0 dm     /
└─live-base 253:1    0   6.5G  1 dm     
loop2         7:2    0    32G  0 loop   
└─live-rw   253:0    0   6.5G  0 dm     /
sda           8:0    0   1.8T  0 disk   
├─sda1        8:1    0     2M  0 part   
├─sda2        8:2    0   500M  0 part   
├─sda3        8:3    0 781.3G  0 part   
│ └─md126     9:126  0   1.5T  0 raid10 
├─sda4        8:4    0     1K  0 part   
├─sda5        8:5    0     1T  0 part   
│ └─md127     9:127  0     2T  0 raid10 
└─sda6        8:6    0  48.8G  0 part   
sdb           8:16   0   1.8T  0 disk   
├─sdb1        8:17   0 781.3G  0 part   
│ └─md126     9:126  0   1.5T  0 raid10 
└─sdb2        8:18   0     1T  0 part   
  └─md127     9:127  0     2T  0 raid10 
sdc           8:32   0   1.8T  0 disk   
├─sdc1        8:33   0 781.3G  0 part   
│ └─md126     9:126  0   1.5T  0 raid10 
└─sdc2        8:34   0     1T  0 part   
  └─md127     9:127  0     2T  0 raid10 
sdd           8:48   0   1.8T  0 disk   
├─sdd1        8:49   0 781.3G  0 part   
│ └─md126     9:126  0   1.5T  0 raid10 
├─sdd2        8:50   0     1T  0 part   
│ └─md127     9:127  0     2T  0 raid10 
└─sdd3        8:51   0  33.2G  0 part   [SWAP]
sr0          11:0    1   4.4G  0 rom    /run/initramfs/live

cat /proc/mdstat
Personalities : [raid10] 
md126 : active (auto-read-only) raid10 sdb1[1] sda3[0] sdd1[3] sdc1[2]
      1638396928 blocks super 1.2 512K chunks 2 near-copies [4/4] [UUUU]
      bitmap: 0/13 pages [0KB], 65536KB chunk

    md127 : active (auto-read-only) raid10 sdb2[1] sdc2[2] sda5[0] sdd2[3]
          2165142528 blocks super 1.2 512K chunks 2 near-copies [4/4] [UUUU]
          bitmap: 0/17 pages [0KB], 65536KB chunk


Reinstalling Grub and running grub2-mkconfig and then the system tries to boot on Fedora 28. Let me know what else I can provide. Could this be related to blscfg?