Would be interesting to see how this works with bigger pools of volatile and persistent memory (disclaimer: I work at Intel on Optane DC SSD/PM-related things).
There's another good paper from a team at UCSD testing all sorts of usages and file systems with NVRAM here too: https://arxiv.org/pdf/1903.05714.pdf.
Sirix sounds like a good fit to take advantage of App Direct access on Optane DCPM, but you're way more of an expert than me. Perhaps make a request for alpha access at GCP to test Sirix with the new tech? https://docs.google.com/forms/d/e/1FAIpQLSeX1tN6Qt-aQUK2iVVi...