Server does not boot in degraded state after loosing one boot-pool drive

The server could not boot up anymore after loosing one (out of two) redundant drives of the boot-pool. SCALE had to be reinstalled to get to a functional state but the problem persisted after a clean install.

The installer used for the clean install is the SCALE-22.03.01.1 installer (fresh downloaded from ixsystems site). The system was again functional after loading a backup configuration file.

After the clean installation the following test was performed to ensure full functionality even in degraded mode:

When removing the first boot-pool disk right after a clean install the server. All went well. It loaded grub on boot up, with menu and all, and the system booted correctly in degraded mode. Then the first disk was inserted again and resilvered. The system was not in degraded mode anymore (the alert dissapeared).
The system was then restarted after removing the second boot drive. The server didn’t boot up this time and the message “this is not a boot drive but a zfs data disk” was displayed (not verbatim but somethig similar). It seems that no grub loader was installed on this remaining disk during the clean Scale installation.
The second boot drive was inserted and the server booted correctly again. I wiped out the first boot drive and added it again to the boot-pool. Then I waited until the resilvering was completed. The "degraded state" warning dissapeared again. Then the second boot drive was removed again and the system restarted. This time it did boot up correctly with that drive only.

Therefore, it seems that the SCALE installer does not install grub on both drives at installation time, but it does when adding disks afterwards to the boot-pool.