No Raid creation possible

You create the RAID first, then create a filesystem on top of the RAID device. You cannot add disks already formatted with ext4 to a MD RAID array. If those ext4 formatted disks hold data, that will be lost. OMV creates RAID arrays from whole devices e.g. /dev/sda and not partition like /dev/sda1. You'd have to start by unmounting any drive shown under filesystems that you want to be in the RAID array and then wiping that drive.

Perhaps consider mergerfs + SnapRAID as a way to combine disks already formatted with ext4 and holding data.

Quote from chente

Remember that Raid is not a backup. If you are thinking of creating a Raid6 with four disks and you do not have a backup, it is always preferable to create two groups with mergerfs and synchronize with rsync.

You will have the same final capacity and a real backup.

https://www.raidisnotabackup.com/

Can you please give a bit more detailed describtion. I'm planning a 4 x 16TB raid 6. I know that a raid is not a backup but i wil not buy another two hdds to have an external backup. What you wrote is new to me so i'm very curious.

i found mergerfs - Perfect Media Server

so i merge 2x16 and 2x16 into two groups and have one being the synconized backup? so no need to have a raid?

Quote from datawh0re

Can you please give a bit more detailed describtion. I'm planning a 4 x 16TB raid 6. I know that a raid is not a backup but i wil not buy another two hdds to have an external backup. What you wrote is new to me so i'm very curious.

i found mergerfs - Perfect Media Server

so i merge 2x16 and 2x16 into two groups and have one being the synconized backup? so no need to have a raid?

If you think, you don't need a RAID when you have a backup, you've never needed a RAID in the first place. You needed a backup.

If your data is remotely important to you, you should by all means make regular (external) backups.

what i need is 32tb drive and something to fall back to in case something happens.

i dont want to split my data across two drives. i could just split the the data and an resync backup them individually. but i want one 32tb drive.

now i wonder, i could just use raid 0 on 2x16 and resync them or use raid 6. where is the advantage of mergerfs?

lets say i have 24tb on the data drive an one physical drive fails, what will be the difference between the 2xraid0 and the mergerfs configuartion?

Quote from datawh0re

what i need is 32tb drive and something to fall back to in case something happens.

i dont want to split my data across two drives. i could just split the the data and an resync backup them individually. but i want one 32tb drive.

now i wonder, i could just use raid 0 on 2x16 and resync them or use raid 6. where is the advantage of mergerfs?

lets say i have 24tb on the data drive an one physical drive fails, what will be the difference between the 2xraid0 and the mergerfs configuartion?

With RAID 0, if you loose one drive, the whole array is lost because every file is split across the drives, but it is faster because the workload and bandwidth is also split across all drives. With MergerFS , if you loose one drive, you loose one drive, so not all data is lost. MergerFS, however, my require occasional balancing of the pool to distribute new files and replicate paths