Linux Doesn't Boot After Replacing /dev/sda in RAID1 (mdadm)

Job ID: 34295984

Budget: $30 – $250 USD

Hello,

I have a Linux Ubuntu 20.04.4 LTS server from OVH. It has a mdadm software raid1 with 4 disks /dev/sda, /dev/sdb, /dev/sdc, /dev/sdb. After replacing disk /dev/sda and restoring the raid, the server doesn't want to boot. I have access to the server via remote netboot rescue mode.

There is how I restored the raid:
sfdisk -d /dev/sdb | sfdisk /dev/sda
mdadm --add /dev/md127 /dev/sda2

I hope you can help me fix the server so it can boot successfully.

I'll give you ssh access to the server via netboot rescue. There is no sensitive or important information on the server.

I want you to fix the server, and then we'll check if it works by booting from the hard drive.
If everything is good, I need a complete list of commands you execute so I can reproduce the fix myself.
Related categories: System Admin Linux Ubuntu