Ceph » RADOS

The most obvious problem is that crush/ uses raw pointers which seems to preclude putting the OSDMaps in memory shared across OSDs. Hmm

Do you mean we need to share a memory region between different osd processes on the same host?

That's the idea, yes. See CERN's 30PB test results: https://cds.cern.ch/record/2015206/files/CephScaleTestMarch2015.pdf

A vague possibility that the future seastar-based OSD may run each logical disk OSD inside a single process, which could share maps — but nothing concrete yet.