[ceph-users] OSD delete vs destroy vs purge

Dear Ceph users, I see that the OSD page of the Ceph dashboard offers three possibilities for "removing" an OSD: delete, destroy and purge. The delete operation has the possibility to flag the "Preserve OSD ID(s) for replacement." option. I searched for explanations of the differences between the three commands but I didn't find anything definitive, so I'd need some help with this. Thanks in advance, Nicola