Digimer! Thanks for the info. Since the HDD0 drive is completely failed, I would need to replace it.. it doesn't have any data on it. The other three HDD's would need the MBR. I am assuming... that because RAID 10 means Striped+Mirroring that HDD 3+4 would be mirrored and 1+2 would be mirrored... is this an accurate statement? On 3/2/2012 12:07 PM, Digimer wrote: > On 03/02/2012 09:03 AM, Jonathan Vomacka wrote: >> CentOS Community, >> >> I have a dedicated server with 4 hard drives in a RAID 10 software >> configuration running LVM. My OS is CentOS 6.2. Earlier today, I >> rebooted my system and my system did not come back online. I opened a >> ticket with my datacenter who informed me that one of my hard drives is >> no longer recognized by the bios and has failed. I was told that an OS >> reinstall was needed. >> >> I don't understand why a reinstall would be necessary when the drives >> are in RAID 10. Apparently when the datacenter did the initial OS >> install, they ONLY installed the MBR on one drive instead of all 4 >> leaving the other 3 drives unbootable. >> >> Is this a way to salvage this with a liveCD without having to reload the >> OS? This server is a very important mail server running OpenLDAP and >> MySQL. I figured maybe I could install the MBR using a liveCD which may >> fix the system. >> >> If an OS reload is the ONLY option, is there a way to reload it without >> touching the /var or /opt filesystems? (yes they were created as a >> seperate partition) however I am not sure if OpenLDAP or MySQL installs >> anything to /usr which I would be completely screwed... >> >> Please help > > Advice provided as-is. > > Boot from a live CD using the CentOS 6.2 install media. Once booted: > > <bash># grub > <grub> root (hd0,0) > <grub> setup (hd0) > <grub> root (hd1,0) > <grub> setup (hd1) > <grub> root (hd2,0) > <grub> setup (hd2) > <grub> quit > <bash># reboot > > This assumes that grub sees the drives at '0, 1 and 2' and the boot > partition is the first on each drive. If it is, when you type 'root > (hdX,0)' it should report that a file system was found. The 'setup > (hdX)' will tell grub to write the MBR to the specified disk. >