Just an fyi... As you would know from reading the LMDB design papers ( http://symas.com/mdb/#pubs ) LMDB is crash-proof by design. A Symas client already confirmed this in their own crash testing last year https://symas.com/carrier-grade-stability-and-performance/ and it has again been verified by a research group at the University of Wisconsin. Their findings are being presented at the Usenix OSDI conference this week, and you can read the paper here https://www.usenix.org/conference/osdi14/technical-sessions/presentation/pil...
They report on a single "vulnerability" in LMDB, in which LMDB depends on the atomicity of a single sector 106-byte write for its transaction commit semantics. Their claim is that not all storage devices may guarantee the atomicity of such a write. While I myself filed an ITS on this very topic a year ago, http://www.openldap.org/its/index.cgi/Incoming?id=7668
the reality is that all storage devices made in the past 20+ years actually do guarantee atomicity of single-sector writes. You would have to rewind back to 30 years at least, to find a HDD where this is not true.
The UWisc researchers' point is that we cannot say what behaviors will be exported by up--and-coming nonvolatile RAM mechanisms (e.g. MRAM or PCRAM); if they offer byte-addressability instead of sector-addressability then there's a potential for these writes to become non-atomic in the future.
At any rate, this issue has zero relevance today, and we are monitoring all of the upcoming NVRAM technologies closely for future developments.
The other takeaway from these reports is how critically unreliable many other popular systems are. If you use any of the other projects that were included in this research, you owe it to yourself to rethink that usage, or raise discussions with their developers on how they plan to address their many weaknesses.
As an interesting footnote, BerkeleyDB was included in the original testing, and while it was in their preliminary results http://wisdom.cs.wisc.edu/workshops/spring-14/talks/Thanu.pdf it is now conspicuously absent from the final paper. Regardless, the OpenLDAP Project is deprecating use of BerkeleyDB for multiple reasons. Again, if you're still using BDB you need to take a moment to re-evaluate your project.