There is for sure way to divide Ceph cluster for SSD or SAS/SATA. You have to edit CRUSHmap. The steps are following: 1. Extract CRUSHmap. 2. Decompile CRUSHmap to txt. 3. Edit CRUSHmap. 4. Compile CRUSHmap. 5. Inject CRUSHmap back in cluster. If you are using same node then basically you have to create a virtual host entry in the CRUSHmap and assign the OSDs to it. This is just way overly simplified version of explanation. If you are not familiar with CRUSHmap and syntaxes used in it, then getting to know it first will help tremendously. Regardless you want to separate cluster or not, knowing CRUSHmap will help you greatly to customize your Ceph cluster. At this time CRUSHmap cannot be edited through proxmox GUI, it can only be viewed.