This feature aims at adding the support for non-persistent SCM (e.g. RAM) by maintaining a copy of the DAOS metadata up-to-date on SSD. Once completed, DAOS will be able to operate in two modes:
persistent SCM: apache/barlow/crow pass, battery-backed DRAM or future SSD products supporting CXL.mem. This is the mode that DAOS supports today over PMDK. No changes will be done to this path.
Persistent SCM Mode (PMDK)
volatile SCM: DRAM or non-persistent CXL.mem memory. This mode requires an extra step on write operations to keep a copy of the metadata in sync on CXL.io/NVMe SSDs.
Changes to support the volatile mode will be implemented in two phase: