Help me understand Centos 7 BTRFS RAID 10 size allocation ?



  • Youtube Video

    Plz watch the video above, Im playing with Centos 7 BTRFS new installation on 4 TB disks (using virtualbox)

    My goal is to create RAID 10 BTRFS on those 4 drives, but no matter what I do I get volume with 1 TB worth of storage, that seems to me like RAID 1 would do ...

    I should get 2 TB worth of real storage.. right ?

    I understand BTRFS Raid is different than the typical RAID we are accustomed to, but is it that different ???

    I even tried with 5 disks now, same thing. Cause I thought perhaps it calculates system drive or boot disk thus the issue/



  • Also I try to edit or change it As Large as Possible, it turns to 256 GB

    0_1490207477629_2017-03-22 20_30_40-Centos 7 BTRFS raid 10 [Running] - Oracle VM VirtualBox.png


  • Service Provider

    Yes. RAID 10 on 4x 1TB drives should result in ~2TB usable space.



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  • That's very odd. I, personally, haven't had good luck with the gui partition manager. For some reason it seems to work differently than what I think it's telling me. Can you boot to a rescue environment and create the RAID array and partitions before starting the installation?