OVH has this guide on what to do after a disk fail on a dedicated server with soft-RAID (ex: two mirrored disks).
I recently had a disk fail on a server with NVMe disks, which requires a EFI-enabled BIOS. Not being very familiar with EFI and NVMe, here are a few random notes:
- "Serial over LAN" (SoL) IPMI at OVH does not work with their "netboot" kernels. The "KVM with Java applet" is required (which requires firefox-esr and java.. ugh).
- When booting with a netboot kernel, use the RAID device as the boot device, i.e.
/dev/md2in my case.
- Double-check the
/etc/fstab. Make sure that the files are present on both devices. Copy over if necessary. I ended up copying the files from another host.
- If you have a swap, make sure you
mkswapon the new disk, since it's not part of the RAID (not a big deal, but will cause boot warnings).
- Update grub on both devices: