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Hello I am about to upgrade my current setup with 6x1tb in a software raid5 using mdadm, to a 3x2tb software raid5 still with mdadm. My problem lies in, that ...
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  1. #1
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    Questions regarding mdadm


    Hello

    I am about to upgrade my current setup with 6x1tb in a software raid5 using mdadm, to a 3x2tb software raid5 still with mdadm.

    My problem lies in, that currently the raid is setup with sda/sdb/sdc/sdd/sde/sdf, and when i plug in the new hdds i assume (havent bought them yet) they will get sdg/sdh/sdi, which will be the new raid.

    This is all good, question is when i unplug my old raid, will the new hdds be "renamed" into sda/sdb/sdc and will that break the raid?

    Can I change hdds device name in the new raid without breaking it? Or will it maybe figure it out automatically

    /Christian

  2. #2
    Linux User ptkobe's Avatar
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    Quote Originally Posted by Godi View Post
    Hello

    I am about to upgrade my current setup with 6x1tb in a software raid5 using mdadm, to a 3x2tb software raid5 still with mdadm.

    My problem lies in, that currently the raid is setup with sda/sdb/sdc/sdd/sde/sdf, and when i plug in the new hdds i assume (havent bought them yet) they will get sdg/sdh/sdi, which will be the new raid.

    This is all good, question is when i unplug my old raid, will the new hdds be "renamed" into sda/sdb/sdc and will that break the raid?

    Can I change hdds device name in the new raid without breaking it? Or will it maybe figure it out automatically

    /Christian
    AFAIK, mdadm uses UUID and superblock info, it doesn't care if it is /dev/sdi or /dev/sdc

    My experience is with ubuntu-server, I will not put my hands on the fire here
    So, please be careful and try to have a contingency plan at hand.

    If you are careful and don't make a mess, you'll be able to mount your old raid again, get functional, and try another go.

    There are other issues, like grub loader and /etc/fstab, that may get confused (but not if it is set with UUID or refer to the mdadm array).

    There's also a grub file that relates to the disks order. See
    $ cat /boot/grub/device.map
    but I don't think you'll need it if you will just be installing a new OS in the new raid.

    Regards
    Luis

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