When OMV7 on Dell r730xd RAID config only sees 9 of 12 HDDs

So, I have a 'new to me' Dell r730xd (basic specs below) that I got OMV7 installed on. Within the Dell PERC RAID controller I created a RAID1 OS array on twin 120GB SSDs on which OMV is installed. That install went mostly smooth as far as my novice self is concerned. As for the storage array... that's a different story.

In OMV under Disks all 12 4tb drive are listed (sda-sdk,sdm) plus the Dell RAID1 at sdl

Under the Multiple Device (aka RAID) tab only 9 HDDs were shown as available for the RAID5.

After reading multiple forum and Linux posts I came across references to checking the drives for previous configs.

lsblk -f

This showed 3 drives with previous FS. Then running the following on all drives sda-j,m (except sdl) from the CLI

wipefs -s /dev/sda

That cleared all the drives and under the Multiple Device tab I was able to create a 12 x 4tb RAID5 structure...now on to adding Plex.

Hope this helps someone else out there.

1. CPUs: 2x (3.20 GHz) 8-Core Xeon E5-2667V4
2. RAM: 64GB
3. Integrated PERC H730
4. 12 x 3.5" front bays (4tb each)
5. 2 x 2.5" rear bays (120gb each)

thanks for the input... yes its a massive raid but its the 3rd backup and not a high risk scenario... i may switch to RAID6 before i copy data over.

i looked for 'hot spare' settings but can't seem to find one, aside from the Dell PERC HotSpare, i was hoping OMV had a setting buried somewhere.