[CentOS] CentOS 6.2 software raid 10 with LVM - Need help with degraded drive and only one MBR

Putting an MBR on all disks right after an OS install, as previously
mentioned, is of course the best option (although it's too late for that
in this instance).  Others have talked about using the live CD to
recover from your situation, which is good.

Other, "less good" options that might be available to you are:
  - change the boot device in the BIOS
  - if the server isn't capable of doing that, have them
    flip the cables.

I, also, would recommend having a little chat with their manager ...

Devin