While trying to research how crush maps are used/modified I stumbled upon these device classes. https://ceph.io/community/new-luminous-crush-device-classes/ I wanted to highlight that having nvme as a separate class will eventually break and should be removed. There is already a push within the industry to consolidate future command sets and NVMe will likely be it. In other words, NVMe HDDs are not too far off. In fact, the recent October OCP F2F discussed this topic in detail. If the classification is based on performance then command set (SATA/SAS/NVMe) is probably not the right classification.
