Are the LMDB files cross-platform compatible?

Question

I would like to know if the LMDB files are cross-platform compatible, more specifically between macOS and Linux. I am trying to import a raw blockchain (that I exported yesterday on macOS) onto a Raspberry Pi 3. However, judging from the current commit rate, it's going to take roughly 19 more days. That isn't feasible. I was thinking, if the LMDB files are compatible, I will just temporarily stop my macOS node, copy over the entire .bitmonero directory, and fire them backup up on both platforms. Would that work?

Note: The .bitmonero directory on the Raspberry Pi 3 is currently on an external USB-attached 5400 rpm drive (exFAT file system).

Update: I copied my .bitmonero directory from macOS to Raspberry Pi (Ubuntu MATE 16.04). Started monerod --detach, seemed to recognize it, so far so good. After about 1h20m, I am still at block 1175453 and daemon is not catching up:

$ monerod status
Creating the logger system
Height: 1175453/1176194 (99.9%) on mainnet, not mining, net hash 25.08 MH/s, v3, up to date, 5+0 connections

I switched to --log-level 1, and am seeing some error messages:

2016-Nov-09 22:42:18.803852 [P2P6]ERROR /DISTRIBUTION-BUILD/src/cryptonote_protocol/cryptonote_protocol_handler.h:94 Unkonown command:1007
2016-Nov-09 22:42:18.804381 [P2P6]ERROR /DISTRIBUTION-BUILD/src/p2p/net_node.h:150 Unkonown command:1007

At --log-level 2 I see an endless series of these errors:

2016-Nov-09 22:56:50.576666 Attempting to get output pubkey by global index, but key does not exist
2016-Nov-09 22:56:50.642883 EXCEPTION: Attempting to get output pubkey by global index, but key does not exist

Not sure how to debug this further …

Answer 1

As of v0.10.0, yes the LMDB files are cross-compatible between 32 and 64bit architectures. They have always been cross-compatible between OSs. They are still byte-order dependent but almost everyone uses little-endian CPUs these days so it's not much of an issue.