How to Recover Server After Power and HD Failure

Discussion in 'HOWTO-Related Questions' started by skinnypete, Aug 21, 2015.

  1. skinnypete

    skinnypete New Member

    Need some help folks! This morning we had a power disruption, we rebooted the server and discovered that one of the drives failed in the process. The server did boot up thanks to RAID5, but when we powered it down again and rebooted we only get the error Kernel panic - not syncing error message. Now we are at a loss! We have a new hard drive on hand but have not replaced the failed one yet because we were planning on removing it from the array first. Right now we are at a loss and don't know what to do. Can someone lead us through the steps to get back up and running? BTW we are running Centos 6.5 (in fact we have the exact same server as described in "The Perfect Server"), thanks in advance!

    Update: We have been able to use the Centos 6.5 Live DVD to get access to our server and can see that all of our directories are still there. (Relief) But still at a loss as to what to do........

    This is what we have done so far:
    1) We replaced the failed hard drive with a new one but not sure what it is named in the raid i.e. /dev/sdb1 /dev/sdc1 /dev/sdd1 or /dev/sde1 (...we are running 5 disks on a software raid5). Therefore we have not copied any partitions over from another disk.
    2) Upon booting we escaped out of the boot screen and tried appending the kernel arguments by adding selinux=0 enforcing=0 but still get the "Kernel panic-not syncing" error on boot.
    3) We have booted the system with the Centos 6.5 install disk and gone into the rescue Centos system option but just get a message that there are no Linux partitions even though the other disks are okay. Then it drops us out to a shell.

    We managed to have a look at the boot log, in summary the only error that we can find is:
    mdadm failed to start array /dev/md/array-name
    input/output error
    Logical Volume Management disabled at boot
    Checking Filesystems OK
    Mounting Filesystems OK
    .......................everything else seems okay.

    Anyone have any ideas as to how to get this server up again?
     
    Last edited: Aug 22, 2015

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