Read only root filesystem

  • Hi all,

    After researching this issue for 2 days (and found nothing) i turn to u!

    After installing omv5 on a brand new usb stick (sandisk ultra fit), after some reboots and plugin installations (flashmemory, omv extras and zfs) trouble starts...

    I cant find for the life of me why the root filesystem gets mounted read only. There are no indications in dmesg, /var/log or anywhere. I also enabled systemd debug logging, but only symptoms of the read only root filesystem show there.

    I reinstalled to another usb stick, same issue, nothing found...

    A mount -o rw remount /dev/sdx1 resolves the problem, but that shouldnt be necessary.

    I changed fstab to use /dev/disk/by-uuid/blablabla.

    I am really pulling my hair here, have read almost everything there is to read about these kinds of issues.

    If anyone has any idea ?

  • I suspect that you need to be a little more systematic.

    Most likely you configure or install something and then the rootfs becomes ro. As you setup your NAS, backup/clone the rootfs after you made some changes and rebooted and verified it works OK. Carry on step by step. When you discover problems, you may be able to determine what the problem is. Just restore the previous working backup and try again. But in smaller steps, to pinpoint the problem.

    Be smart - be lazy. Clone your rootfs.
    OMV 5: 9 x Odroid HC2 + 1 x Odroid HC1 + 1 x Raspberry Pi 4

  • Well, i changed fstab to:

    #UUID=2ce0d0be-b078-4cbb-833b-ebebca11a22f / ext4 rw,noatime,nodiratime,errors=remount-ro 0 1

    /dev/disk/by-uuid/2ce0d0be-b078-4cbb-833b-ebebca11a22f / ext4 rw,noatime,nodiratime,errors=continue 0 1

    which to my knowledge "should" mount the root filesystem rw even if there are errors on the filesystem.

    As dmesg reveals, the root filesystem is mounted, the second mount was my manual mount:

    [ 4.278186] EXT4-fs (sdf1): mounted filesystem with ordered data mode. Opts: (null)

    [ 257.697477] EXT4-fs (sdf1): re-mounted. Opts: errors=continue

    Strange thing here is that the mount during boot gives "Opts:(null)"?

  • After a couple of reinstalls:

    it seems that mergerfs causes this due to: ,x-systemd.requires=

    Changed fstab from:




    and that (for now) solved the issue

  • OS = USB stick

    Device Boot Start End Sectors Size Id Type

    /dev/sde1 * 2048 13326335 13324288 6.4G 83 Linux

    /dev/sde2 13328382 30029823 16701442 8G 5 Extended

    /dev/sde5 13328384 30029823 16701440 8G 82 Linux swap / Solaris

    data = 3 x 2 disk zfs mirrors

    1 mergerfs folder

    and the change to fstab was of course: fsname=xbmc:913a0c94-a502-4f17-88e1-abdaf86f08f0/store1/store2

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