Unable to delete RAID array

    Hello all,


    I've recently installed OMV on a HP Microserver, using a 64GB SSD as the OS disk and three 1TB HDDs to run in RAID 5. The idea being that I can periodically backup the usable 1.86TB from the array to a standalone 2TB USB drive.


    However after several clean installs of OMV, much reading and a great deal of frustration I cannot create a RAID5 array with the three 1TB HDDs.


    In the raid configuration section, one drive is already listed as a clean, degraded, mirror and I cannot delete it or wipe it. It allowed me to recover it and add disks to the mirror but, even after leaving it overnight to rebuild, I could not delete the newly built array - I could wipe/remove the added disks but not the first disk.


    The error message that pops up reads:

    Code
    Failed to execute command 'omv-rmraid /dev/md127': mdadm: ARRAY line /dev/md/MicroServer:2 has no identity information.
mdadm: Cannot get exclusive access to /dev/md127:Perhaps a running process, mounted filesystem or active volume group?


    If I pull the disk and drop it in my USB caddy, windows can see it, wipe it and run it just fine but, as soon as I plug it back into the Microserver and boot up, it is displayed as the degraded mirror again.


    Short of putting a hammer through the HDD and buying a replacement, I am at a loss.


    Please tell me I'm missing something obvious, I can take the embarrasment if it means I can build my RAID 5 array.


    Thanks in advance for any help


    GB

    So what is the status of the raid (cat /proc/mdstat)? Does it list a raid? If it does, you can try to assemble it first, then delete it from the web GUI. If you want to just destroy it, you can do that by wiping the first few sectors of the drive. The first trick is to get OMV's web GUI to not see it as part of the raid and I would imagine that depends on what /proc/mdstat says. You can also `grep md127 /etc/openmedivault/config.xml` to see what OpenMediaVault is configured with.

    No problem:


    cat -> Print the contents of a file to standard output (the screen by default)
    /proc/mdstat -> The /proc filesystem is a virtual FS where the kernel places bits of information. The "md" in mdstat stands for "Multiple Device", and is one of Linux's device management systems. So "cat /proc/mdstat" is asking Linux to tell you about the status of any multiple device configurations, like RAID.


    grep -> Search a file or set of files for particular string or expression and output all lines that match. "md127" seems like the device name for your raid, based on the error output you gave. /etc is the main directory for configuration information for your system. /etc/openmediavault/config.xml is where OpenMediaVault stores configuration settings that are made in the web GUI. So we're asking it to find any configuration entries that relate to the raid device you talked about. Once we have that, combined with the above, we can get an idea of what your system thinks about your raid, and how best to make it not think those things.


    You can use "man" (for manual) on virtually any command to get more information.


    "man cat"
    "man grep"
    "man mdadm"

    I stripped the server down to clean out some dust and change the RAM.


    When I put it back together, I tried cat /proc/mdstat and it didn't list the degraded mirror!?


    Anyhoo, I logged in via the webgui and found that all three 1TB drives are now showing as available for RAID5. I have no idea why, nor do I care, but I'm happy to give you the credit for it, ikogan. Thank you. :thumbup:


    It's also nice to join a new community and receive a quick response to a First Post cry for help.


    Best regards
    GB

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