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Journal files. You can begin a transaction, crash, and lose the transaction. But the thing itself will be consistent. Perhaps there's something funny about the
by jfoutz 9y ago
Journal files. You can begin a transaction, crash, and lose the transaction. But the thing itself will be consistent.
Perhaps there's something funny about the failure modes of non-volatile memory that's different than a disk. Replication can improve things, sure. there's always a chance of a cosmic ray doing something weird to your stuff. That's (so far) a lot less common than a regular old crash.
- skybrian 9y agoI was thinking along the lines of the machine being on the wrong side of a network partition and then disappearing entirely. Cloud services are supposed to survive the loss of any single machine.
- jfoutz 9y agoAh, i think you're right, but that's a different problem. The Jepsen talks are enlightening, as so many errors get highlighted. Ultimately, if your algorithm is right, the hardware won't matter at all. Each node could be a person with pencil and paper, and the messages are lossy paper airplanes. The NVM stuff (i think) just changes parameters to cache size, journal log size, stuff like that. I mean, it's cool tech, and it'll probably make stuff faster. But the reliability comes from the architecture and faithful implementation.