How do I recreate a broken mirror?

Posted on 2008-11-05
Last Modified: 2008-12-04
I have an IBM Server using with 2 identical drives.  They are split into 3 partitions. 30GB, 50GB 70GB, C, F, O respectively.  After a power cut, I look and there are 6 partitions.  In Disk manager, the 2 drives are shown with identical sizes.  When a created a new folder under C it was not reflected on it's mirrored counterpart.  In device manager I have the following;
Intel 82801GB Serial ATA Storage Controller - 27C0
Intel 82801GB Ultra ATA STorage Controller - 27DF.  I do not think these are raid controllers.
It would seem that luckily, I have lost the RAID controller but my data is still safe and the Server still boots.  What can I do to recreate the mirror?
Question by:jcp-it
    LVL 14

    Expert Comment

    Unfortunately, having booted the machine with the two devices disjointed means that they are now out of sync.  The first thing you need to do is toast (wipe) the other drive (the one that does NOT have C: on it).

    Next, you need to re-create the mirror using whatever means used the first time.  If the server has a hardware RAID controller, use the BIOS or the RAID management utility to re-create the mirror.  If it's the onboard Intel ICHxR RAID controller, you may need to enter the server's BIOS and switch the controller back to RAID mode instead of Legacy or AHCI mode (the power outage could have zapped your CMOS settings).

    If it was a software RAID, then you just use Disk Manager to re-RAID them.

    All of it depends on how your machine was configured in the first place.
    LVL 7

    Accepted Solution

    I've done this without scrubbing the drives.  You state that the raid controller was lost, so I am assuming it is hardware.  Is it a card?  If the controller blew on the motherboard you pretty much need an identical mobo.  If it is a card and no longer is found, replace the card.  If it is a mobo raid, make sure that it didn't get reset to off in the BIOS before looking for another motherboard.

    That said, all you have to do is go into the raid utility and tell it to mirror, it will tell you that all data will be destroyed on the second drive, say yes and it will rebuild.  Based on disk size, I would suspect it will take some time to rebuild the mirror.
    LVL 1

    Author Comment

    I went into the bios, enbled raid and it started to synchrnise straight away.  I looked in the RAiD config and it said both drives were healthy and optimal.  But the server did not boot.
    Disconnect Drive 2, and it ran a checkdisk and boots (complaining of a service not starting).
    How do I know go about connecting Drive 2 and mirroring.  
    LVL 1

    Author Comment


    Sorry for the delay in replying and I appreciate the advice given.
    There was a few fairs at the clients site so making changes to IT system was not wise as downtime would not be acceptable.

    So I let it run off 1 drive for a while.  I loaded IBM's ServeRaid 8. I created an image backup using Acronis to save my bacon.  I connected the 2nd drive and in the RAID Utility checked that all disks werew present and that it was set to mirror.  I was given the option to rebuild array in BIOS or for rebuild during operation in the ServeRAID utility in Windows.  It is still rebuilding as I write this.

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