This is similar to this question:
HP G8 migrate RAID0 to RAID1 with CLI commands
But different enough that I think it is worth asking as a new question.
I have a Gen 10 HPE server with the P408i-a RAID controller.
Currently it just has a single disk, which it is treating as a 1 disk RAID0 array.
I want to add two more disks to it, and convert the result to a RAID5 array.
From ssacli, I can see "add" and "modify" options, but it isn't that clear how to combine this to do what I want.
In particular, under the help for the "add" command, it says "adding physical drives is the same as expanding an array", which to me implies that as soon as I run the "add", it will start a conversion to a 3 disk RAID0, which isn't what I want.
If I add the new drives as spares, and then run the modify command, will that work (i.e. will it work out it needs to absorb the spares to do the conversion)?
Best Answer
As the server was running VMware ESXi, backing up and restoring would have been very time consuming. What I ended up doing, which worked for me, was the following three HPE commands (after inserting the new drives), with many hours of waiting in between as it completed the operation.
(wait for several hours as RAID0 array reshapes)
(wait for several hours as RAID0 array changes to RAID5)
Because "give the usable space to the visible drive" is a separate stage from "reshape the RAID array", the OS didn't see the intermediate state where the array appeared as a 3 disk RAID0 array.
I then followed the process at this link to get the VMware layer to see the additional space, which worked without needing any reboots:
https://michlstechblog.info/blog/esxi-expand-datastore-from-command-line/