I’m just carrying out some unplanned maintenance on my Proxmox server that is kind of stressing me out. I thought no might also be a good time to upgrade the rpool’s hardware, which currently consists of a janky mix of 1x SATA SSD, and a two NVMe SSDs, one of which is newly installed and is to be part of a 2 disk mirror, along with another, identical NVMe disk. I plan to remove the SATA SSD, and the older, smaller, NVMe disk. I’d also like to update Proxmox on account of the recently discovered but longstanding bug with ZFS… but I don’t want any more stress on my plate in the form of a failed software upgrade.
So I was wondering whether there’s any way of removing one of the SSDs from the rpool before I carry out the upgrades, so that in the event something goes wrong, I can still go back to and boot from the SSD that was remove? In Oracle’s ZFS docs, it says-
You cannot boot directly from a disk that has been detached from the system by using the zpool detach command. You also cannot boot from an active root pool disk that is currently offline. However, on an x86 based system with a modern BIOS and the boot order is set correctly and the root pool is mirrored, the system will boot from the second disk automatically even if the primary boot disk is offline or detached.
What if I just physically remove and replace the disk, without detaching it first? Would I be able to boot from it then?