Comment 3 for bug 2031157

When my lab stops with the error in the bug description, then it usually due to that microceph is already installed from a previous attempt and is currently using the disks, or the disks weren't cleaned up.

You can check if microceph is currently using the disks by running:
sudo microceph disk list

The output will contain two blocks.

Disks configured in MicroCeph:
+-----+----------+------+
| OSD | LOCATION | PATH |
+-----+----------+------+

Available unpartitioned disks on this system:
+-------------+-----------+------+----------------------------------------+
| MODEL | CAPACITY | TYPE | PATH |
+-------------+-----------+------+----------------------------------------+

If the device is listed in the first block, then you need to remove it from microceph with the following command:
sudo microceph disk remove <OSDNUMBER> --bypass-safety-checks

If it is in the second block, or the command doesn't work, you need to clear it with wipefs:
sudo wipefs -a -f <DEVICEPATH>

You should see "bytes were erased at offset" in the output if it was successfully cleared.