Re: Raid Array and Changing Motherboard

["Alexander V. Makartsev" <avbetev@gmail.com>]

On 02.07.2023 22:23, Mick Ab wrote:

I have a software RAID 1 array of two hard drives. Each of the two disks contains the Debian operating system and user data.

I am thinking of changing the motherboard because of problems that might be connected to the current motherboard. The new motherboard would be the same make and model as the current motherboard.

Would I need to recreate the RAID 1 array for the new motherboard I.e. re-initialise the current RAID 1 disks and repopulate the disks with data or can I just set up the software RAID on the new motherboard without affecting the current data on the RAID 1 drives ?

    It's hard to tell what exactly will happen, because it depends on
    BIOS/Firmware of the motherboard, even though there is a special
    metadata record on each disk, which contains role of the disk and
    configuration of the RAID array. I predict two outcomes:
    1. Two disks connected to a new motherboard will be recognized by
    BIOS/Firmware right away after you switch controller mode from AHCI
    to RAID, and appear as existing RAID1 array.
    2. Two disks connected to a new motherboard will appear as two
    normal disks and won't be recognized as a RAID1 array, asking you to
    create\init array.
    
    In case #2 data on disks will be lost, so before you do any
    manipulations make and verify backups.
    Usually BIOS RAID software is very basic and won't allow to preserve
    current data on disks, or select a role (primary/secondary) for the
    disks, or create incomplete RAID1 array using only one disk to allow
    to copy data over from the second disk.
    
    If you happen to have any other two old disks on hand, I suggest you
    to experiment with those on current motherboard, i.e. create an
    additional new RAID1 array and see if that array stays intact after
    simulated disks "transfer".
    You can simulate disks transfer by powering of the computer,
    disconnecting the test disks and check if test RAID1 array still
    listed.
    If test array will be listed and report two test disks missing then
    array information is also recorded in BIOS and this array
    information won't be on a new motherboard.
    However, if there won't be any information about test array, then it
    should appear when you reconnect test disks and data on test disks
    should be intact.
    
    There could be also a manual available from motherboard's
    manufacturer which could give some clues about what is possible and
    what would happen.

--
With kindest regards, Alexander.

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