RAID 1 BTRFS on OMV7

1st Official Post

    Hello,
    I made a new installation with OMV7,

    I want to use for data, two 3TB disk (/dev/sda and /dev/sdb) in Mirror Mode with BTRFS file system.
    What are the correct steps?
    I need to install the plugin for RAID/Multiple Device or as it seems I can create a mirror BTRFS directly from the file system page in the web gui?
    my doubt is because I tried in that way, but there were some strange results.....

    1) the size of the filesystem is reported as the sum of the 2 disks (so not as expected in mirror mode)
    2) the new disk in some place is named as /dev/sda (or maybe /dev/sdb) that are the name of the 2 original disks...I was expecting something like /dev/md0 or a new name
    thanks for help

  • Endar

    Added the Label OMV 7.x

  • Endar

    Changed the title of the thread from “RAID 1 BTRFS” to “RAID 1 BTRFS on OMV7”.
    • Official Post

    You don't need the md plugin for btrfs raid.

    /dev/md0 would be md raid.

    You create btrfs raid 1 by going to Storage -> Filesystems

    Then click on "Create and mount a filesystem"

    Select BTRFS

    Change the Profile to Raid 1.

    Select the two disks you want to use in the array.

    If you don't see any disks, they either need to be wiped or you are trying to select usb disks which are not supported in raid arrays.

    omv 7.4.14-1 sandworm | 64 bit | 6.11 proxmox kernel

    plugins :: omvextrasorg 7.0 | kvm 7.0.15 | compose 7.2.16 | k8s 7.3.1-1 | cputemp 7.0.2 | mergerfs 7.0.5 | scripts 7.0.9


    omv-extras.org plugins source code and issue tracker - github - changelogs


    Please try ctrl-shift-R and read this before posting a question.

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    yes... I did as you say, but, the size that is the sum, is expected?

    and just to understand, there is no a new device but I can use /dev/sda or /dev/sdb and the system keeps them aligned? sorry for the silly question

    • Official Post
    Quote from Endar

    the size that is the sum, is expected?

    No. Raid 1 is a mirror. So, the array should be the size of the smallest drive.

    omv 7.4.14-1 sandworm | 64 bit | 6.11 proxmox kernel

    plugins :: omvextrasorg 7.0 | kvm 7.0.15 | compose 7.2.16 | k8s 7.3.1-1 | cputemp 7.0.2 | mergerfs 7.0.5 | scripts 7.0.9


    omv-extras.org plugins source code and issue tracker - github - changelogs


    Please try ctrl-shift-R and read this before posting a question.

    Please put your OMV system details in your signature.
    Please don't PM for support... Too many PMs!

    Ok thank you.
    the 2 disk,before were in a RAID5 of 3 disk (so size is the double with 3 disk of same size), maybe there is some metadata not deleted with wipe disk operation.


    one of the two I'm sure I've done a complete Secure Wipe, the other just 10% of Secure Wipe and the rest with Fast...Maybe I will try a complete Secure Wipe on both.

    • Official Post
    Quote from Endar

    the 2 disk,before were in a RAID5 of 3 disk (so size is the double with 3 disk of same size), maybe there is some metadata not deleted with wipe disk operation.

    I'm not sure I follow. There will be no metadata left after a disk wipe. It is expected that raid5 of three 2.73 TB disks will give you a 5.46 TB array. It is expected that raid 1 of two 2.73 TB disks will give you a 2.73 TB array. What are you seeing? You haven't given any real numbers.

    omv 7.4.14-1 sandworm | 64 bit | 6.11 proxmox kernel

    plugins :: omvextrasorg 7.0 | kvm 7.0.15 | compose 7.2.16 | k8s 7.3.1-1 | cputemp 7.0.2 | mergerfs 7.0.5 | scripts 7.0.9


    omv-extras.org plugins source code and issue tracker - github - changelogs


    Please try ctrl-shift-R and read this before posting a question.

    Please put your OMV system details in your signature.
    Please don't PM for support... Too many PMs!

    After the creation of the filesystem (I copied the text inside "Code" in my post #5) the summary tell me:

    Filesystem size: 5.46TiB
    also in the OMV dashboard and in the filesystem webpage was reported 5.46TiB

    but now....

    not sure what happened, after a copy of a file on the disk maybe.
    Is reported correctly 2.73Tib....
    so maybe everything is ok now... I'm a little confused sorry :/ ^^
    thanks for the support

    happened to me as well

    created btrfs raid1-mirror

    reported size was the sum of both disks

    after copy data to it it reported correct size

    OMV7

    Can confirm the same is happening for me. OMV 7.0.5-1 (Sandworm)


    Quote from HTWingNut

    Same issue here. 7.3.1-1 (Sandworm)


    Others stated after copying data it corrected itself. It has not for me.

    What do get if you click on the details icon for your BTRFS filesystem? What is in shown in the "Diagnostics > Report" if you search on "information about BTRFS filesystems"?

    Quote from HTWingNut

    Same issue here. 7.3.1-1 (Sandworm)


    Others stated after copying data it corrected itself. It has not for me.

    After I made a file transfer, this total got corrected to show the mirrord size, previously was showing the total size of my two drives. I am on BTRFS RAID1 filesystem on 7.4-9-2 (sandworm).

    is it possible to add one disk to make mirror without wipe and deleting existing data? I found it's possible via cli, but wondering if will be posible also via GUI. Or if I do it via cli, if GUI will correctly recognize it?

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