(Per a forum user conversation in another thread) Grow RAID 5
After testing RAID 5 scenarios in VM's of OMV 3.0.73, versus a real world platform running OMV 2.1:
It seems that the behavior of the "Grow" button in <System>, <RAID Management> has changed between OMV versions 2.X and 3.X.
Where the "Grow" button in OMV 2.1 triggers an array restrip operation that integrates a new drive, the "Grow" button in 3.X versions simply adds a drive to the array as a hot spare which is more in line with the mdadm --add command line.
To integrate a disk into an OMV 3.x array (Grow it) it was necessary to do it from the command line (as follows).
mdadm --grow /dev/md0 --raid-devices=4
Perhaps there's a reason for the change?
If restriping (or Growing) a RAID 5 array is to be supported in OMV 3.X , it makes sense to attach the CLI operation (mdadm --grow /dev/md0 --raid-devices=4) to the Grow button in RAID Management.
Similarly, when adding a hot spare to an array, it would be more intuitive if a new GUI "Add" button is attached the CLI operation (mdadm --add /dev/md0 /dev/sde).
Are we off base or are we missing something? In any case, any information or an explanation would be appreciated.