Expanding 5 disk raid to 6 disk raid 5

Operating System ZimaOS
1

Zima OS 1.5.3
I have been running on Zima on a Lazycat LC-03 NAS succesfully for several weeks.
It is set up with a single pool in raid 5 with 2 SSD’s and 3 NVME’s (all 4TB). No spinning disks.
I just added a 6th NVME (4TB); which is recognized. When I try to expand the existing 5 drive array by the new disk. I get an error "mdadm: add new device failed for/dev/ nvme1n1 as 6:invalid argument

2

I believe this is a ZimaOS 1.5.3 limitation, not a disk or hardware fault.

Why it fails

  • ZimaOS uses mdadm, but online RAID5 expansion (5 → 6 disks) isn’t reliably supported.
  • The invalid argument error means the array cannot be reshaped in place, even though the new NVMe is detected.

What I suggest (safe path)

  1. Back up all data.
  2. Delete the existing RAID5 pool.
  3. Recreate RAID5 with all 6 NVMe disks at once.
  4. Restore data.

Do not

  • Force mdadm --grow from CLI unless you accept data loss.

I believe future ZimaOS releases will improve this, but in 1.5.3 this is effectively unsupported.

3

Thanks for the reply. I was afraid that was going to be the answer.

4

Thanks for the advice.

Next challenge; Zima will not let me break and format the existing array.

I have rebooted several times over two days and

Every attempt results in “maybe RAID is being used by kernel, please try again later”.

5

I believe this means the RAID is still mounted / in use (kernel has the md device open), so ZimaOS refuses to stop it.

What I suggest (quick + safe):

  1. Stop all apps first
  • Go App Store > Installed
  • Stop everything (anything using /DATA will block RAID stop)
  1. Reboot once
  • Then try delete/format again

If still stuck, use SSH to confirm what’s holding it:

cat /proc/mdstat
mount | grep md
lsblk -f

If you paste that output, I can tell you exactly what process/mount is blocking it and the cleanest way to release it (without harming the OS).