New user trying to get started. Rpi 4 (8Gb) + mdadm RAID + OMV 6

New guy here; I apologize if this has been answered elsewhere and I failed to find it after searching the forums.

I've found lots of how-to tutorials with OMV to enable a mdadm software-managed RAID on a RPi with OMV. Apparently everything I've studied on referenced OMV 5 and I've installed OMV6. I have created my mdadm software-managed RAID array on my RPi 4 but I'm not able to select it as a device when trying to create a new file system in OMV6; OMV6 sees the two USB-connected hard drives as individual devices when trying to create the file system but it does not see the RAID array, which is apparently a different behavior than what existed in OMV 5. So, my question: Can I use a mdadm software managed RAID on a RPi with two USB-connected SATA hard drives to create a file system for OMV6 to manage? Also, FWIW, OMV6 does see the array and reports it properly in the RAID Management section under Storage; it just won't let me select it as a device when creating a new File System.

In the tutorials I came across, they all showed the RAID array listed in the RAID Management section as a Device in the drop-down when creating a new file system. I see my array in the RAID management section but it isn't available in the new file system drop list of devices. Is this a change in behavior with OMV6? Or was a RAID array of drives connected via USB never visible as devices when creating a new file system?

Zitat von geaves

That's interesting, what command did you use to create the array

I used mdadm to create the array on the Pi itself (outside of OMV's UI); it showed up almost immediately in the Raid Management section of OMV6 while it was syncing / initializing the array and now it shows "Clean" as the state of the array.

Zitat von chente

Read the warning at the end of this link.

https://openmediavault.readthe…ration/storage/raid.html#

You can possibly find a way to do it, but everyone here will advise against it. The OMV6 GUI may not allow this. I do not know, I do not use USB disks.

Do yourself a favor and follow the recommendations in the OMV documentation. If you have questions ask here, the tutorials and videos that are on the internet may not be the correct thing that they should be.

Thank you for the links and guidance. I very much appreciate it. I guess the updated GUI of OMV6 has fixed an unintended feature that allowed for RAID arrays built on drives mounted via USB to be used as devices for OMV-managed file systems.

Zitat von geaves

What specifically, the full line you used

sudo mdadm --create /dev/md0 --level=1 --raid-device=2 /dev/sdb1 /dev/sdc1

sudo mkfs -t ext4 /dev/md0

Zitat von geaves

this is why I love the internet, both of the above commands are incorrect, at least as far OMV is concerned.

Do you know what /dev/sdb1 is

Do you know what mkfs is

If you can answer those, it will explain why you can't create a file system on OMV

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yes, and yes... Hopefully the docs that chente pointed me to will explain why OMV thinks that a perfectly valid RAID array with a valid file system on it is not an acceptable device (whereas it used to allow for it in prior versions).

geaves I'll leave now. I would have hoped that a "moderator" would not incite conflict but rather help shut it down when it happens and maybe even provide guidance to folks hoping to learn from the experience of others. If you won't tell me what I've done wrong or point me to an authoritative place to learn it (which chente did), I don't understand what value you think you're adding to the conversation other than building self-importance.

(/dev/sdb1 is the first (and in my case, only) partition of a hard drive visible to my OS; maybe you're laughing at me for using a partition instead of the drive, ie: /dev/sdb?)

Zitat von geaves

If you want information on how to do this properly and it work, I'll supply it

This is ultimately what I've been trying to ask for while also learning something about what I evidently did wrong but don't yet know what that was.

Thank you. It seems that using mdadm to create the array against two partitions is my ultimate problem, I guess? I think a large part of my confusion is that the array, as originally created (against /dev/sdb1 and /dev/sdc1), does appear in Raid Management in OMV but /dev/md0 does not appear under Storage -> Disks. I'll give this a shot.